Effective Aeromonas specific monoclonal antibody for immunodiagnosis

Objective:To identify the monoclonal antibody specific to Aeromonas spp.,a Gram negative bacteria causing gastroenteritis and wound infection.Methods:The monoclone,namely 88F2-3F4,was produced from hybridoma technology.The specificity of antibody secreted from 88F2-3F4 was tested against other Gram negative bacteria frequently found in gastrointestinal tract.Then the antibody was used for searching Aeromonas antigens in artificial seeded rectal swab cultures by dot-blot enzyme linked immunosorbent assay.Results:88F2-3F4 produced an antibody that recognized an antigen with a molecular mass of 8.5 kDa in all 123 isolates of the seven Aeromonas species tested,but recognized no epitope of any other Gram-negative bacterium typically found in the gastrointestinal tract.A dot-blot enzyme linked immunosorbent assay based on this antibody showed 86.49％ sensitivity and 92.13％ specificity.Conclusions:88F2-3F4 monoclonal antibody could react with all Aeromonas isolates,but not other Gram negative bacteria,therefore it should be a useful tool for the detection of Aeromonas antigen in clinical and environmental samples.

A single injection of 19 kDa carboxy-terminal fragment of Plasmodium yoelii merozoite surface protein 1 (PyMSP119) formulated with Montanide ISA and CpG ODN induces protective immune response in mice.

Objective: To investigate the efficacy of a vaccine formulation of the 19 kDa conserved carboxyl-terminal fragment of Plasmodium yoelii merozoite surface protein-1 (PyMSP119) formulated with CpG ODN 1826 and Montanide ISA51 or ISA720 when used to immunize mice by a single injection. Methods: Groups of BALB/c mice were immunized parenterally with one, two or four injections with PBS or PyMSP119 formulated with CpG ODN in ISA51 or ISA720. Sera were collected weekly and assessed for total IgG and IgG subclass titers. Protection was tested by challenge infection with P. yoelii YM. Results: Interestingly, single injection immunization showed the same kinetics of antibody responses as two- or four-injection immunization. However, the peak antibody response induced by PyMSP119 in CpG ODN and ISA51 appeared earlier than that induced by PyMSP119 in CpG ODN and ISA720 (28 days vs 41 days). At day 63 after the first injection, the PyMSP119-specific IgG antibody levels by single injection and four- injection immunizations were not different. However, the levels of the IgG2a antibody subclass were significantly lower by single injection immunization with PyMSP119 in CpG ODN and ISA720. The antibodies were sustained at high levels for at least 20 weeks. After challenge infection, all mice immunized by a single injection of PyMSP119 in CpG ODN and ISA51 survived with low-grade parasitemia, while 50% of mice immunized with PyMSP119 in CpG ODN and ISA720 died with high levels of parasitemia. Conclusion: These findings suggest that MSP119 immunization by a single injection can induce protective immunity, particularly when formulated with an appropriate strong adjuvant.

IgG antibody profile to c-terminal region of Plasmodium vivax merozoite surface protein-1 in Thai individuals exposed to malaria.

Naturally acquired immune response to C-terminal region of Plasmodium vivax merozoite surface protein1 (PvMSP1) in 200 individuals with recent clinical episodes of malaria from malaria endemic areas along Thai-Myanmar border in the west and Thai-Cambodia border in the east of Thailand was evaluated by enzyme-linked immunosorbent assay (ELISA). The anti-PvMSP1-IgG antibody was observed in 110 individuals (55%). Among IgG responders, IgG1 coexpressed with IgG3 were the predominant subclasses. The levels of anti-PvMSP1 total IgG, IgG1 and IgG3 antibody response seem to be increased with age although no detectable significant correlation was found (r = 0.004, p = 0.484 for total IgG; r = 0.035, p = 0.386 for IgG1; r = -0.600, p = 0.142 for IgG2; r = 0.077, p = 0.227 for IgG3; r = 0.664, p = 0.051 for IgG4). However, the mean level of specific total IgG was highest in the age group of >40 years. These levels of either specific total IgG or each IgG isotype did not vary among individuals with different malaria episodes. A higher level of specific total IgG, IgG1 and IgG3 antibody response related with the lower of parasitemia density was observed although no significant correlation was found. Our data indicate that individuals exposed to vivax malaria in Thailand developed antibodies to the potential candidate vaccine antigen, PvMSP1 (C-terminal).

The effects of Porphyromonas gingivalis LPS and Actinobacillus actinomycetemcomitans LPS on human dendritic cells in vitro, and in a mouse model in vivo.

Interaction between different bacterial plaque pathogens and dendritic cells may induce different types of T helper (Th) cell response, which is critical in the pathogenesis of periodontitis. In this study we investigated the effects of lipopolysaccharide (LPS) from Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans on human monocyte-derived dendritic cells (Mo-DCs) with respect to co-stimulatory molecule expression, cytokine production and Th cell differentiation. Unlike Escherichia coli and A. actinomycetemcomitans LPS, P. gingivalis LPS induced only low levels of CD40, CD80, HLA-DR and CD83 expression on Mo-DCs. LPS from both bacteria induced considerably lower TNF-alpha and IL-10 than did E. coli LPS. LPS from all three bacteria induced only negligible IL-12 production. In a human mixed-leukocyte reaction, and in an ovalbumin-specific T cell response assay in mice, both types of LPS suppressed IFN-gamma production. In conclusion, stimulation by P. gingivalis LPS and A. actinomycetemcomitans LPS appears to bias Mo-DCs towards Th2 production.

A survey of the Th2R and Th3R allelic variants in the circumsporozoite protein gene of P. falciparum parasites from western Thailand.

Allelic variation in the Plasmodium falciparum circumsporozoite protein (CS) gene has been determined by sequencing the immunodominant T-cell epitopes, Th2R and Th3R, from 95 isolates from two malaria-endemic areas in the west of Thailand. Comparison with a reference sequence revealed only non-synonymous point mutations in the two epitope regions. Point mutations were found outside these epitopes in a minority of samples, and all but four were also non-synonymous. A relatively high number of variants, 11 Th2R and 9 Th3R, were detected and comprised some that had not been previously observed. However, the Th2R*05 and the Th3R*01 allelic variants predominated, as they were found in more than 70% of the 101 sequences obtained.