Blood group changes in acute myeloid leukemia and their relationship with therapeutic effect / 中国输血杂志

【Objective】 To explore the blood group changes of two acute myeloid leukemia patients with suspected O type, and their relationship with the therapeutic effect. 【Methods】 Serological analysis of ABO blood group of patients was carried out by microcolumn gel method, tube method and absorption-elution test, ABO blood group genotyping was performed by microfluidic chip method. Exons E2 to E7 of ABO gene were amplified by PCR and sequenced by Sanger method. 【Results】 The forward typing of two cases were both O type, but the reverse typing were both A type. The absorption-elution test results all showed detection of antigen A. ABO gene phenotype of the two cases were both A, with genotyping results as A102/A102 and A102/O01, respectively. Sequencing results showed that SNP sites of ABO blood group were 467T/T, 261G/delG and 467C/T, respectively.In one case, the intensity of anti-A agglutination reaction changed significantly from weak to strong with the progress of treatment. 【Conclusion】 For clinical samples of acute myeloid leukemia patients with ABO forward and reverse typing discrepancy and suspected O type, the result of reverse typing should be valued, and absorption-elution test should be performed to further confirm the ABO blood type combining the genetic test results, so as to develop appropriate blood transfusion strategies for patients.

Effect of thimerosal on vaccine antigen activity and its mechanism / 中国生物制品学杂志

@#Abstract： Thimerosal is commonly used as a preservative in biological products，especially in vaccines. Although it has been removed from single ⁃ dose vaccines in most countries，thimerosal is still widely used in multi ⁃ dose vaccines at present. Thimerosal，as a component in vaccine preparation，should be compatible with other components，especially should not damage the activity of antigen. However，in recent years，many studies have reported that thiomersal can reduce the antigenicity and immunogenicity of vaccine antigens，especially protein antigens containing or rich in cysteine（Cys）， suggesting that the effect of thimerosal on vaccine antigen activity should be fully evaluated when it is used as a vaccine preservative. In this paper，the effects of thimerosal on antigenicity and immunogenicity of two inactivated vaccines and three recombinant protein vaccines and the possible mechanisms were reviewed，in order to provide reference for rational selection of vaccine preservatives.

Research progress in antigenic evolution of influenza A (H3N2) virus / 中华微生物学和免疫学杂志

Influenza viruses are common pathogens causing respiratory infections in humans. Among the four seasonal influenza viruses, influenza A virus H3N2 has become the leading cause of seasonal influenza illness and death, posing a great threat to public health and the economy. Since it first emerged and caused a pandemic in 1968, H3N2 has been circulating repeatedly in human beings and continually evades host immune attack by antigenic drift, resulting in a decrease in vaccine efficacy. In this paper, the antigenic evolution of influenza A virus H3N2, the impact of antigenic evolution on the selection of vaccine strains and some models for predicting the evolution of influenza viruses were analyzed and reviewed, which paved the road for understanding the antigenic evolution of influenza virus and vaccine development.

Clonamiento, expresión y seroreactividad de la proteína recombinante de ensamblaje de lipopolisacáridos - D (LptD) de Bartonella bacilliformis / Cloning, expression and seroreactivity of the recombinant lipopolysaccharide assembly protein - D (LptD) from Bartonella bacilliformis

RESUMEN Objetivo. Evaluar in silico y a nivel serológico el potencial antigénico del dominio extracelular recombinante de la proteína de ensamblaje de lipopolisacáridos - D (LptD) de Bartonella bacilliformis (dexr_LptD). Materiales y métodos. Mediante el análisis in silico se realizó la selección de una proteína de B. bacilliformis con potencial antigénico e inmunogénico. El gen de la proteína seleccionada se clonó en Escherichia coli TOP10 y se expresó en Escherichia coli BL21 (DE3) pLysS. La proteína recombinante fue expresada usando isopropil-β-D-1-tiogalactopiranósido (IPTG) y se optimizaron las condiciones de inducción. Por último, se purificó con resina Ni-IDA (His60 Ni Superflow) y se realizó un ensayo de Western Blot. Resultados. In silico, la proteína seleccionada fue LptD por estar localizada en la membrana externa y ser antigénica e inmunogénica. Las condiciones optimizadas para la inducción del dexr_LptD fueron 0,5 mM IPTG, 16 h, medio TB (Terrific Broth), etanol al 3% (v/v), 28 ºC, OD600: 1-1,5 y 200 r.p.m. La purificación se realizó en condiciones denaturantes a pequeña escala y se obtuvo 2,6 µg/mL de dexr_LptD parcialmente purificada. El ensayo de Western Blot mostró una reacción positiva entre los sueros provenientes de pacientes con la enfermedad de Carrión y dexr_LptD, ello evidencia la antigenicidad del dexr_LptD. Conclusiones. El dexr_LptD muestra antigenicidad in silico y a nivel serológico, estos resultados son base para posteriores estudios sobre candidatos vacunales contra la enfermedad de Carrión.

ABSTRACT Objective. To evaluate in silico and at the serological level the antigenic potential of the recombinant extracellular domain of the lipopolysaccharide assembly protein - D (LptD) of Bartonella bacilliformis (dexr_LptD). Materials and Methods. Through in silico analysis, we selected a B. bacilliformis protein with antigenic and immunogenic potential. The selected protein gene was cloned into Escherichia coli TOP10 and expressed in Escherichia coli BL21 (DE3) pLysS. Recombinant protein was expressed using isopropyl-β-D-1-thiogalactopyranoside (IPTG) and induction conditions were optimized. Finally, it was purified with Ni-IDA resin (His60 Ni Superflow) and a Western Blot assay was conducted. Results. In silico, the selected protein was LptD because it is located in the outer membrane and is antigenic and immunogenic. Optimized conditions for dexr_LptD induction were 0.5 mM IPTG, 16 hours, TB (Terrific Broth) medium, 3% (v/v) ethanol, 28 ºC, OD600: 1-1.5 and 200 rpm. Purification was carried out under denaturating conditions on a small scale and we obtained 2.6 μg/mL of partially purified dexr_LptD. The Western Blot assay showed a positive reaction between the sera from patients with Carrión's Disease and dexr_LptD, which shows the antigenicity of dexr_LptD. Conclusions. The dexr_LptD shows antigenicity both in silico and at the serological level, these results are the basis for further studies on vaccine candidates against Carrion's Disease.

Variation of SARS-CoV-2 spike protein and its effects on neutralization sensitivity / 中华微生物学和免疫学杂志

The COVID-19 epidemic that occurred at the end of 2019 spreads rapidly to all parts of the world, putting the global public health system to a severe test. With the continuation of the epidemic, SARS-CoV-2 variants are constantly emerging. In particular, the mutation of the spike protein can cause changes in the infectivity and antigenicity of the virus, resulting in an increase in the infectivity and a decline in the protective efficacy of existing vaccines, and even the replacement of epidemic strains. This is also one of the reasons why the epidemic has not been effectively controlled so far. Nowadays, the main circulating variants have changed their characteristics to a certain extent, and the neutralization sensitivity of some variants to neutralizing monoclonal antibodies, immune sera and convalescent sera has decreased to a certain extent compared with the original strains. The emergence of variants is not only related to the characteristics of the virus itself, but also to the changes of transmission host and the chronic infection in people with deficient immunity. The emerging variants should be closely monitored, and their functional characteristics should be systematically studied so as to provide data for vaccine research and development and the designation of immunization strategies.

Capsid destabilization and epitope alterations of human papillomavirus 18 in the presence of thimerosal / 药物分析学报

Thimerosal has been widely used as a preservative in drug and vaccine products for decades.Due to the strong propensity to modify thiols in proteins,conformational changes could occur due to covalent bond formation between ethylmercury(a degradant of thimerosal)and thiols.Such a conformational change could lead to partial or even complete loss of desirable protein function.This study aims to investigate the effects of thimerosal on the capsid stability and antigenicity of recombinant human papillomavirus(HPV)18 virus-like particles(VLPs).Dramatic destabilization of the recombinant viral capsid upon thimerosal treatment was observed.Such a negative effect on the thermal stability of VLPs preserved with thimerosal was shown to be dependent on the thimerosal concentration.Two highly neutralizing antibodies,13H12 and 3C3,were found to be the most sensitive to thimerosal treatment.The kinetics of antigenicity loss,when monitored with 13H12 or 3C3 as probes,yielded two distinctly different sets of kinetic parameters,while the data from both monoclonal antibodies(mAbs)followed a biphasic expo-nential decay model.The potential effect of thimerosal on protein function,particularly for thiol-containing proteinaceous active components,needs to be comprehensively characterized during formulation development when a preservative is necessary.

Comparison of the antigenicity of African swine fever virus p35 protein as diagnostic antigen / 生物工程学报

In order to screen African swine fever virus (ASFV) diagnostic antigen with the best enzyme linked immunosorbent assay (ELISA) reactivity. By establishing the ELISA method, the diagnostic antigen of ASFV p30 protein expressed by baculovirus-insect cell expression system as reference, we explored the antigenic properties and diagnostic potential of ASFV p35 protein expressed by prokaryotic expression system as a diagnostic antigen. The results of Western blotting and immunofluorescence show that the molecular weight of the recombinant p35 protein and p30 protein obtained was 40 kDa and 30 kDa, respectively, and these two proteins had good immuno-reactivity with ASFV positive serum. Recombinant p30 and p35 proteins were used as diagnostic antigens to establish ELISA, and the sensitivity and repeatability of these methods were tested. The results show that although the detection sensitivity of the p30-ELISA established in this study was higher than that of the p35-ELISA, the sensitivity of p35-ELISA was 95.8%, and variations in intra- and inter-assay repeatability of the two methods were less than 10%. The coincidence rate between the p35-ELISA and the imported kit was 97.2%. Results show that p35-ELISA was sensitive and stable, and could detect specific antibodies against ASFV.

Antigenicity and adhesiveness of a Plasmodium vivax VIR-E protein from Brazilian isolates

BACKGROUND Plasmodium vivax, the major cause of malaria in Latin America, has a large subtelomeric multigene family called vir. In the P. vivax genome, about 20% of its sequences are vir genes. Vir antigens are grouped in subfamilies according to their sequence similarities and have been shown to have distinct roles and subcellular locations. However, little is known about vir subfamilies, especially when comes to their functions. OBJECTIVE To evaluate the diversity, antigenicity, and adhesiveness of Plasmodium vivax VIR-E. METHODS Vir-E genes were amplified from six P. vivax isolates from Manaus, North of Brazil. The presence of naturally acquired antibodies to recombinant PvBrVIR-E and PvAMA-1 was evaluated by ELISA. Binding capacity of recombinant PvBrVIR-E was assessed by adhesion assay to CHO-ICAM1 cells. FINDINGS Despite vir-E sequence diversity, among those identified sequences, a representative one was chosen to be expressed as recombinant protein. The presence of IgM or IgG antibodies to PvBrVIR-E was detected in 23.75% of the study population while the presence of IgG antibodies to PvAMA-1 antigen was 66.25% in the same population. PvBrVIR-E was adhesive to CHO-ICAM1. MAIN CONCLUSIONS PvBrVIR-E was antigenic and adhesive to CHO-ICAM1.

Antigenicity and genetic characterization of HA gene in influenza B/Victoria-lineage virus in Beijing 2017-2018 / 中华实验和临床病毒学杂志

Objective@#To understand the antigenicity and genetic characterization of influenza B virus HA gene in B/Victoria-lineage virus (BV) in Beijing during 2017-2018.@*Methods@#Thirty BV virus strains isolated from MDCK cell culture by 17 laboratories in Beijing were collected. The antigenicity was analyzed by comparing with the vaccine strain recommended by WHO. The total viral nucleic acid was extracted and HA gene was amplified by RT-PCR and sequenced. The phylogenetic tree was constructed by HA and mutant sites were analyzed.@*Results@#Among 30 strains of BV, 23 strains (76.7%) were low-reactive strains, other 7 strains (23.3%) were related to the vaccine. The phylogenetic analysis showed that the HA gene of all 30 strains located in Clade 1A branch. In addition, amino acid mutations occurred in 8 sites, and 6 of them located in the antigen determining region.@*Conclusions@#There was a correlation between the high proportion of low-reactive antigenicity and 6 aa variation in antigenic determinants involved in HA region of BV influenza virus between 2017-2018, which provides an important laboratory basis for the recommendation of BV influenza vaccine.

Evaluation of the antigenicity of Dnak and MPT83 proteins of Mycobacterium tuberculosis / 中华微生物学和免疫学杂志

Objective To evaluate the antigenicity of two proteins of Mycobacteium tuberculosis (M. tuberculosis), Dnak(Rv0350) and MPT83(Rv2873), in order to provide a scientific basis for immuno-logical diagnosis of tuberculosis and research on vaccines. Methods The two antigen proteins, Dnak (Rv0350) and MPT83(Rv2873), were cloned, expressed and purified using the methods of genetic recom-bination and protein purification technology. Blood samples were collected from subjects including tuberculo-sis patients ( TB) , non-tuberculosis patients with other pulmonary diseases ( non-TB) and healthy volunteers (HV). To analyze the immunological properties of the recombinant Dnak (Rv0350) and MPT83 (Rv2873) proteins, they were used as antigens to detect humoral and cellular immunity in the subjects with enzyme linked immunosorbent assay ( ELISA ) and effector T cell enzyme-linked immunospot assay ( ELISPOT ) . Results The recombinant and purified Dnak (Rv0350) and MPT83 (Rv2873) proteins of M. tuberculosis were successfully obtained and used as antigens in the detection of humoral and cellular immunity in the sub-jects. Specific antibodies ( IgG) in the serum samples of 135 TB, 56 non-TB and 94 HV were tested with ELISA. The results showed that the sensitivity, specificity and accuracy of Dnak ( Rv0350 ) protein were 77. 80％ (105/135), 56. 70％ (85/150) and 66. 67％ (190/285). Similarly, the sensitivity, specificity and accuracy of MPT83 (Rv2873) protein were 76. 30％ (103/135), 43. 30％ (65/150) and 58. 95％(168/285). Cellular immunity was tested with the levels of IFN-γproduced by effector T lymphocytes after stimulating peripheral blood monouclear cells ( PBMC) collected form subjects of 59 TB, 65 non-TB and 64 HV with Dnak (Rv0350) and MPT83 (Rv2873) protein antigens. The results showed that the sensitivity, specificity and accuracy of Dnak (Rv0350) and MPT83 (Rv2873) proteins were 66. 10％ (39/59), 62. 79％ (81/129) and 63. 83％ (120/188), and 47. 46％ (28/59), 79. 84％ (103/129) and 69. 68％(131/188), respectively. Conclusions M. tuberculosis Dnak (Rv0350) and MPT83 (Rv2873) proteins have good antigenicity and could stimulate T cells to produce stronger immune responses. The two proteins used in combination might have promising potential in the research of immunodiagnosis of tuberculosis and the development of new anti-tuberculosis vaccines.

Perfil imunogênico de vacinas inativadas contra agalaxia contagiosa em ovinos / Immunogenic profile of inactivated vaccines against contagious agalactia in sheep

Este trabalho teve como objetivo avaliar o perfil imunogênico em ovinos de três vacinas produzidas com linhagens brasileiras de Mycoplasma agalactiae. O perfil proteico do antígeno vacinal foi avaliado por SDS-PAGE e a imunogenicidade da vacina pela técnica de Western blot. A vacina foi inativada com formol, adsorvida em hidróxido de alumínio (Vacina 1), Montanide IMS-2215 (Vacina 2), Montanide Gel-01 (Vacina 3) e administradas em três doses. Entre a primeira e a segunda dose houve um intervalo de 21 dias, e entre a segunda e a terceira de 180 dias. O pool de soros de dez ovinos coletados nos períodos 0, 21, 35, 90, 150, 210, 270 e 360 dias pós-vacinação foram testados pela técnica de Western blot. A vacina 2 foi mais antigênica, com detecção de anticorpos 21 dias após a primeira dose. Para as vacinas 1 e 3, os anticorpos são verificados após 35 dias, com queda acentuada aos 90 dias; apenas anticorpos contra a proteína de 48 kDa apareceram após a terceira dose de forma discreta. Contra a vacina 2, ainda persistiram anticorpos contra as proteínas de 48, 55 e 80 kDa nos períodos 90, 150 e 210, que aumentaram após a terceira dose. Conclui-se que a vacina 2 induziu a resposta humoral de forma estável contra proteínas de M. agalactiae.

This study aimed to evaluate the immunogenic profile in sheep of three vaccines produced with a field Brazilian strains of Mycoplasma agalactiae. The vaccine protein profile was evaluated by SDS-PAGE and vaccine immunogenicity by Western blot. The vaccine was inactivated with formaldehyde and adsorbed onto three different adjuvants: with aluminum hydroxide (Vaccine 1), Montanide IMS 2215 (Vaccine 2), and Gel Montanide-01 (Vaccine 3). The vaccine was administered in three doses. Between the first and second dose there was an interval of 21 days, and between the second and the third one of 180 days. A pool of ten sera collected in 0, 21, 35, 90, 150, 210, 270 and 360 days after first vaccination were tested by Western blot techniques. The second vaccine was more antigenic with antibody detection 21 days after first dose. For both vaccines 1 and 3, antibodies were present 35 days after first dose, with a significant drop at 90 days; only antibodies against 48 kDa protein discreetly appeared after the third dose. Stimulation induced by vaccine 2 produced antibodies against 48, 55 and 80 kDa proteins that persisted until 90, 150 and 210 days after first dose, which rose again after third dose. It was concluded that the vaccine 2 induced stable humoral immunity against M. agalactiae proteins.

Immunoglobulin E-binding Proteins of Cooked Walnuts in Korean Children

PURPOSE: The immunological characteristics of young Korean children with walnut (WN) allergy and the influence of different cooking methods on WN proteins have not been evaluated to date. This study aimed to evaluate the major WN allergens identified among Korean children, together with changes in WN antigenicity caused by common cooking methods. METHODS: We enrolled children under the age of 13 years with WN serum-specific immunoglobulin (Ig) E concentrations. The protein fractions of dry-fried and boiled WN extracts were compared with those of raw WNs using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), 2-dimentional gel electrophoresis (2DE) and a proteomic analysis using electrospray ionization (liquid chromatography-mass spectrometry [LC-MS]). An immunoblotting analysis was conducted to examine IgE reactivity toward raw WNs using serum samples from 6 children with a clinical WN allergy. To determine the processed WN proteins with IgE-binding capacity, a 2D-immunoblotting analysis was performed using the pooled sera of 20 WN-sensitized children. RESULTS: Protein bands from raw WNs were identified at 9, 16, 28, 52, 58, and 64 kDa via SDS-PAGE. The 9- and 16-kDa protein bands were enhanced by boiling, whereas the 52- and 64-kDa bands were considerably diminished. On LC-MS analysis, of the 66 IgE-binding proteins present in raw WNs, 57 were found in dry-fried WNs, but only 4 in boiled WNs. The sera of 5 out of 6 participants reacted with the 52-kDa protein bands and those of 4 out of 6 participants reacted with the 16- and 28-kDa protein bands, respectively. Meanwhile, a 2D-immunoblotting result confirmed the presence of different binding patterns among children who consumed cooked WNs. CONCLUSIONS: The protein profile of boiled WNs is substantially different from that of raw WNs. However, 4 proteins including prolamins remained stable after dry-frying or boiling. Further studies are needed to evaluate the clinical relevance of these findings.

Development and properties of hypoallergenic infant formula

Milk proteins are composed of casein, further classified into αS1-casein, αS2-casein, β-casein, and κ-casein, and whey protein, which is separated into α-lacatalbumin, β-lactoglobulin, serum albumin, and some minor proteins, such as lactoferrin and immunoglobulin. To reduce the allergenicity of protein, heat treatment and enzymatic protein hydrolysis by endopeptidase are necessarily required. Additionally, membrane technology should be applied to produce a protein hydrolyzate, which has consistent molecular weight of peptide and low in free amino acid without allergenic peptide or protein. Extensive casein hydrolyzate and whey protein hydrolyzate are used for protein source of mainly extensively hydrolyzed protein formula (eHF) intended for the treatment of cow's milk allergy. Also, partially hydrolyzed formula (pHF) is developed, which is using a single protein source e.g., whey protein hydrolyzate. The allergenicity of infant formula can be determined according to molecular weight profile and antigenicity reduction compared to intact protein. More than 90% peptides are present in eHF have a molecular weight of 10,000 Da. Generally, antigenicity reduction in eHF and pHF is 10-6 and 10-3, respectively. Even if protein hydrolyzate is manufactured under strict quality control, there is still a risk of cross contamination of allergenic milk components through environmental conditions and the shared manufacturing process. Thus, quality assessment of protein hydrolyzate formula must be performed routinely.

Research in immunological characteristics of recombinant Rv3425 protein of my-cobacterium tuberculosis / 中国免疫学杂志

Objective:To study the immunological characteristics of recombinant Rv3425 protein,to evaluate its diagnosis value and the role in the pathogenicity. Methods: Rv3425 gene was cloned into pET28a vector,the recombinant protein was induced and purified;we analyzed the antigenicity and specificity of Rv3425 by ELISA ( Enzyme-linked immuno sorbent assay) and Western blot methods,apoptosis effect of Rv3425 to macrophage was deteced by FCM ( Flow cytometry method ) . Results: Purified prokaryotic expressed protein Rv3425 was acquired,we found Rv3425 could elicit high level of IFN-γin spleen cells and combine with the serum of iH37Rv (inactivated mycobacterium tuberculosis) immunized mice;the specific IgG and IgM antibodies of TB (Tuberculosis) patients were significantly higher than healthy donors;Rv3425 also could induce the necrosis of macrophage. Conclusion:Our study found that Rv3425 had strong antigenicity and could induce the apoptosis of macrophage,these findings were very important for the research of TB diagnosis and pathogenicity.

Implications of newly-added N-glycosylation mutation of hepatitis B virus s-gene in patients with coexistence of HBsAg and antiHBs / 解放军医学杂志

Objective To analyze the characteristics of newly added N-glycosylation mutation in major hydrophilic region (MHR) of HBV S gene in patients with coexistence of HBsAg and antiHBs, and reveal the generation mechanism and clinical implications of the coexistence. Methods HBV S genes from 284 patients with HBsAg+antiHBs and 314 patients with single HBsAg were amplified respectively for sequence analysis. A chronic hepatitis B (CHB) patient with HBsAg+antiHBs in MHR was found to harbor a novel double N-glycosylation mutation and selected for further study. Recombinant vectors harboring the novel mutant or control PreS/S genes were constructed and transfected in HepG2 cells respectively for phenotypic analysis, and the effects of the mutations on HBV duplication and antigenicity were investigated. Results The detection rate of MHR N-glycosylation mutation was significantly higher in HBsAg+antiHBs group than in single HBsAg group (11.3% vs. 2.9%, P<0.01, respectively). In HBsAg+antiHBs cohort, the proportion of hepatocellular carcinoma (HCC) patients accounted for 46.9%(15/32) in patients with N-glycosylation mutation at the time of testing; by contrast, the number was 22.6%(57/252) in patients with non-N-glycosylation mutation (P<0.01). N-glycosylation mutational pattern of the novel strain was s116-118TST → NST+s131-133TSM → NST concomitant with sP120 deletion+G145D mutation. The novel mutants accounted for 98.0%, 2.0% and 2.5%, respectively, of viral clones in three sequential serum samples. Mutants with single N-glycosylation mutation s130-132GTS→NSS without sP120 deletion+G145D were detected in sample 2, accounting for 17.6% of viral clones. Compared to the wild-type, the novel mutant had an increase of 31% in replication capacity, but a decrease of 99% in HBsAg level. Immunofluorescence showed that elimination of the two additional N-glycosylation mutations only partly restored HBsAg detection by antiHBs, suggesting that sP120 deletion+G145D mutation also attenuated HBsAg antigenicity. Conclusions Additional N-glycosylation mutation in MHR of HBV S gene is associated with coexisting HBsAg+antiHBs, and the two parameters together might be a better risk factor for HCC occurrence. Combination of two additional N-glycosylation mutation, sP120 deletion and sG145D mutation may co-play a role in silence of HBsAg antigenicity.

Prediction of promiscuous T-cell epitopes in the Zika virus polyprotein: An in silico approach

Objective To predict immunogenic promiscuous T cell epitopes from the polyprotein of the Zika virus using a range of bioinformatics tools. To date, no epitope data are available for the Zika virus in the IEDB database. Methods We retrieved nearly 54 full length polyprotein sequences of the Zika virus from the NCBI database belonging to different outbreaks. A consensus sequence was then used to predict the promiscuous T cell epitopes that bind MHC 1 and MHC II alleles using PorPred1 and ProPred immunoinformatic algorithms respectively. The antigenicity predicted score was also calculated for each predicted epitope using the VaxiJen 2.0 tool. Results By using ProPred1, 23 antigenic epitopes for HLA class I and 48 antigenic epitopes for HLA class II were predicted from the consensus polyprotein sequence of Zika virus. The greatest number of MHC class I binding epitopes were projected within the NS5 (21%), followed by Envelope (17%). For MHC class II, greatest number of predicted epitopes were in NS5 (19%) followed by the Envelope, NS1 and NS2 (17% each). A variety of epitopes with good binding affinity, promiscuity and antigenicity were predicted for both the HLA classes. Conclusion The predicted conserved promiscuous T-cell epitopes examined in this study were reported for the first time and will contribute to the imminent design of Zika virus vaccine candidates, which will be able to induce a broad range of immune responses in a heterogeneous HLA population. However, our results can be verified and employed in future efficacious vaccine formulations only after successful experimental studies.

Characterization of Pv92, a Novel Merozoite Surface Protein of Plasmodium vivax

The discovery and understanding of antigenic proteins are essential for development of a vaccine against malaria. In Plasmodium falciparum, Pf92 have been characterized as a merozoite surface protein, and this protein is expressed at the late schizont stage, but no study of Pv92, the orthologue of Pf92 in P. vivax, has been reported. Thus, the protein structure of Pv92 was analyzed, and the gene sequence was aligned with that of other Plasmodium spp. using bioinformatics tools. The recombinant Pv92 protein was expressed and purified using bacterial expression system and used for immunization of mice to gain the polyclonal antibody and for evaluation of antigenicity by protein array. Also, the antibody against Pv92 was used for subcellular analysis by immunofluorescence assay. The Pv92 protein has a signal peptide and a sexual stage s48/45 domain, and the cysteine residues at the N-terminal of Pv92 were completely conserved. The N-terminal of Pv92 was successfully expressed as soluble form using a bacterial expression system. The antibody raised against Pv92 recognized the parasites and completely merged with PvMSP1-19, indicating that Pv92 was localized on the merozoite surface. Evaluation of the human humoral immune response to Pv92 indicated moderate antigenicity, with 65% sensitivity and 95% specificity by protein array. Taken together, the merozoite surface localization and antigenicity of Pv92 implicate that it might be involved in attachment and invasion of a merozoite to a new host cell or immune evasion during invasion process.

Prediction of promiscuous T-cell epitopes in the Zika virus polyprotein: An in silico approach

OBJECTIVE@#To predict immunogenic promiscuous T cell epitopes from the polyprotein of the Zika virus using a range of bioinformatics tools. To date, no epitope data are available for the Zika virus in the IEDB database.@*METHODS@#We retrieved nearly 54 full length polyprotein sequences of the Zika virus from the NCBI database belonging to different outbreaks. A consensus sequence was then used to predict the promiscuous T cell epitopes that bind MHC 1 and MHC II alleles using PorPred1 and ProPred immunoinformatic algorithms respectively. The antigenicity predicted score was also calculated for each predicted epitope using the VaxiJen 2.0 tool.@*RESULTS@#By using ProPred1, 23 antigenic epitopes for HLA class I and 48 antigenic epitopes for HLA class II were predicted from the consensus polyprotein sequence of Zika virus. The greatest number of MHC class I binding epitopes were projected within the NS5 (21%), followed by Envelope (17%). For MHC class II, greatest number of predicted epitopes were in NS5 (19%) followed by the Envelope, NS1 and NS2 (17% each). A variety of epitopes with good binding affinity, promiscuity and antigenicity were predicted for both the HLA classes.@*CONCLUSION@#The predicted conserved promiscuous T-cell epitopes examined in this study were reported for the first time and will contribute to the imminent design of Zika virus vaccine candidates, which will be able to induce a broad range of immune responses in a heterogeneous HLA population. However, our results can be verified and employed in future efficacious vaccine formulations only after successful experimental studies.

Identification of Immunodominant B-cell Epitope Regions of Reticulocyte Binding Proteins in Plasmodium vivax by Protein Microarray Based Immunoscreening

Plasmodium falciparum can invade all stages of red blood cells, while Plasmodium vivax can invade only reticulocytes. Although many P. vivax proteins have been discovered, their functions are largely unknown. Among them, P. vivax reticulocyte binding proteins (PvRBP1 and PvRBP2) recognize and bind to reticulocytes. Both proteins possess a C-terminal hydrophobic transmembrane domain, which drives adhesion to reticulocytes. PvRBP1 and PvRBP2 are large (> 326 kDa), which hinders identification of the functional domains. In this study, the complete genome information of the P. vivax RBP family was thoroughly analyzed using a prediction server with bioinformatics data to predict B-cell epitope domains. Eleven pvrbp family genes that included 2 pseudogenes and 9 full or partial length genes were selected and used to express recombinant proteins in a wheat germ cell-free system. The expressed proteins were used to evaluate the humoral immune response with vivax malaria patients and healthy individual serum samples by protein microarray. The recombinant fragments of 9 PvRBP proteins were successfully expressed; the soluble proteins ranged in molecular weight from 16 to 34 kDa. Evaluation of the humoral immune response to each recombinant PvRBP protein indicated a high antigenicity, with 38-88% sensitivity and 100% specificity. Of them, N-terminal parts of PvRBP2c (PVX_090325-1) and PvRBP2 like partial A (PVX_090330-1) elicited high antigenicity. In addition, the PvRBP2-like homologue B (PVX_116930) fragment was newly identified as high antigenicity and may be exploited as a potential antigenic candidate among the PvRBP family. The functional activity of the PvRBP family on merozoite invasion remains unknown.

The effect of heat treatment or hydrolysis on cow's milk protein distributions and antigenicities

PURPOSE: Cow's milk protein is one of the most common and strongest food allergen. We investigated the effects of heat treatment on the distribution and antigenicities of major allergens from cow's milk. We also compared the protein distribution and antigenicities among cow's milk formula and its substitutes. METHODS: We heated alpha-casen, beta-lactoglobulin (BLG), alpha-lactalbumin (ALA), and crude extract of cow's milk in 100degrees C boiling water for 1 hour. We prepared crude extracts from cow's milk formula, partially hydrolyzed milk formula (pHF) and extensively hydrolyzed milk formula (eHF). The protein compositions of all the samples were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The antigenicities were determined by IgE immunoblotting with pooled serum collected from 11 patients with milk allergy. RESULTS: After heating, no significant alteration was found in casein, and the aggregates of ALA and BLG were detected with molecular weights of about 30 and 45 kDa, respectively. The antigenicities of newly detected aggregates were increased. The new aggregates of BLG with increased antigenicities were also found in heated milk total protein. Major milk allergens were not found in pHF, and residual components with a molecular weight below 10 KDa did not show IgE-binding activity. We failed to observe the residual components and antigenicities of eHF. CONCLUSION: Changes in protein distribution and antigenicity of milk total protein induced by heat treatment may not be significantly different from those of each major allergen. The residual components of pHF could have little IgE-binding capacity, and there may be few or no antigenic components in eHF.