Gastric carcinoma associated with Menetrier's-like disease in a West Highland white terrier.

A seven-year-old West Highland white terrier was presented for chronic vomiting associated with mild regenerative anaemia and hypoalbuminaemia. Further examination showed a giant polypoid cerebriform mass located in the lesser curvature of the stomach. Partial gastrectomy was performed and histology was consistent with hypertrophic gastritis with typical features of Ménétrier's disease. Five years after surgery, the dog was re-examined for recurrence of vomiting episodes. Endoscopy showed ulceration of the lesser curvature of the stomach and histological analysis revealed a poorly differentiated superficial gastric carcinoma surrounded by hypertrophic gastritis. To the authors' knowledge, this is the second time that coexistence of these two types of lesions is reported, suggesting that recurrence of gastritis could be the starting point of the tumoural process.

N-terminal region of the PB1-F2 protein is responsible for increased expression of influenza A viral protein PB1.

Influenza A virus (IAV) PB1-F2 protein is encoded by an alternative reading frame (+1) within the PB1 gene. PB1-F2 has been shown to contribute to the pathogenesis of influenza virus infection as well as to the secondary bacterial infection. More recently has been shown that PB1-F2 protein may regulate a viral RNA (vRNA) polymerase activity by the interaction with PB1 protein. We proved that PB1-F2 protein increased the level of expression of PB1 protein and vRNA in the infected cells. Moreover, we demonstrated that a higher level of vRNA expression resulted in the increase of expression of multiple viral proteins, including NP, M1, and NS1. Finally, we used plasmids expressing N-terminal (1-50 aa) or C-terminal (51-87 aa) region of the PB1-F2 molecule for transfection of MDCK cells co-infected with influenza A/Puerto Rico/8/34 (H1N1) virus deficient in the PB1-F2 protein expression (PR8ΔPB1-F2). These experiments clearly showed that N-terminal region of PB1-F2 protein was responsible for the increase in PB1 protein expression. C-terminal region of PB1-F2 protein had no effect. Thus, we have identified the important function for N-terminal region of PB1-F2 protein.

Effect of proteasome inhibitors on expression of HLA-G isoforms.

HLA-G primary transcript is alternatively spliced into a number of mRNAs. In addition to full length HLA-G1 protein isoform these mRNAs might also encode truncated HLA-G protein isoforms lacking one or two extracellular domains. Whereas HLA-G1 protein isoform is regularly identified, truncated HLAG protein isoforms are not detected even if all alternative spliced mRNAs are present in cells. The absence of entire domain(s) renders the truncated HLA-G protein isoforms incapable of binding peptide and beta2-microglobulin. These features of truncated HLA-G protein isoforms may result in their rapid degradation by proteasomes. Here we show that despite the presence of all alternatively spliced HLA-G transcripts in JEG-3 cells pretreated with proteasome inhibitors only a full length HLA-G1 protein isoform was regularly detected. Interestingly, immunoblot analysis showed slight increase of HLA-G1 protein in cells pretreated with proteasome inhibitors, although the expression of HLA-G1 transcript was basically not affected. Expression of HLA-G3 transcript increased in JEG-3 cells pre-incubated with LLL, however, neither HLA-G3 nor other HLA-G short protein isoform was regularly detected. In K562 transfectants proteasome inhibitor LLL greatly enhanced expression of the HLA-G1 and -G2 transcripts as well as corresponding protein isoforms. Flow cytometry analysis showed that in cells pre-treated with proteasome inhibitors cell surface expression of HLA-G1 protein decreased but the quantity of intracellularly localized HLA-G antigens increased. Altogether our results suggest that truncated HLA-G proteins isoforms are not detected in JEG-3 cells as a result of their instability and the low translation efficiency of truncated HLA-G transcripts.

Immunity in latent Herpes simplex virus infection.

Immune responses against productive Herpes simplex virus 1 (HSV-1) and/or Herpes simplex virus 2 (HSV-2) (HSV) infection together with associated immune escape mechanisms are to a great degree understood. Due to a limited RNA expression and lacking a convincing evidence for production of virus proteins during latency, HSV in latently infected neurons had been for a long period considered invisible to immune system. This review analyzes currently accumulating data indicating an important role of immune response to HSV-1 latency and/or to early steps of HSV-1 reactivation process. Although this review focuses on HSV-1, it is likely that general concepts apply to both HSV-1 and HSV-2, since they share a great deal of similarity in their biological features including a high degree of sequence similarity at the nucleic acid level.

Sexually transmitted infections among prostitutes in Bratislava, Slovakia.

Sera from 18 prostitutes from Bratislava were examined for the presence of antibodies to several sexually transmitted pathogens, namely Herpes simplex virus 2 (HSV-2), Human immunodeficiency viruses 1 and 2 (HIV-1 and HIV-2), Hepatitis B and C viruses (HBV and HCV), Chlamydia trachomatis, and Treponema pallidum. Results of this screening indicated that 11 prostitutes (61%) carried 1 or more sexually transmitted infections. The most prevalent antibodies were directed against HSV-2 (9 cases, i.e. 50%), which represents the most common sexually transmitted infection agent.

Characterization of glycoprotein C of HSZP strain of herpes simplex virus 1.

Sequences of UL44 genes of strains HSZP, KOS and 17 of herpes simplex virus 1 (HSV-1) were determined and the amino acid sequences of corresponding glycoproteins (gC) were deduced. In comparison with the 17 strain, the HSZP strain showed specific changes in 3 nucleotides and in 2 amino acids (aa 139 and 147, both from Arg to Trp) in the antigenic locus LII. The change at aa 147 was situated within the GAG-binding epitope. In a similar comparison, KOS strain had changes in 3 nucleotides and 3 amino acids (aa 3, 14, and 300). The UL44 genes of HSZP and KOS strains were expressed in insect Sf-21 cells by means of the baculovirus (Bac-to-Bac) expression system. As shown by immunoblot analysis, both the recombinant baculoviruses (B1-HSZP and B6-KOS) expressed a glycosylated gC, the M(r) of which (116 K) was lower than that of gC synthesized in Vero cells (129 K) infected with strains HSZP or KOS. In addition, smaller gC-specific proteins (of apparent M(r) of 50-58 K and 98 K) corresponding to a non-glycosylated precursor polypeptide and/or incomplete forms of the partially glycosylated gC were found. When Balb/c mice were immunized with Sf-21 cells expressing gC, the recombinant gC-HSZP represented a more efficient immunogen possibly due to its stronger expression in these cells. The corresponding gC-HSZP antiserum reacted in enzyme-linked immunosorbent assay (ELISA) equally well with HSZP and KOS virion antigens and neutralized HSZP strain at a low titer. Both gC-HSZP and gC-KOS antisera detected the homologous as well as the heterologous gC antigens in Vero cells regardless whether infected with strains HSZP, KOS or 17, revealing the presence of gC from 6 to 16 hrs post infection (p.i.) in the cytoplasm, on the nuclear membrane and at the cell surface.

Prevalence of antibodies to herpes simplex virus 2 among homosexual men either positive or negative for human immunodeficiency viruses in Slovakia.

We determined the prevalence of antibodies to herpes simplex virus 2 (HSV-2, HSV-2 antibodies) in sera of homosexual men either positive for human immunodeficiency virus 1 (HIV-1, HIV+, a group of 27 sera) or negative for HIV-1 and HIV-2 (HIV-, a group of 52 sera) in Slovakia. Antibodies to HSV-2 glycoprotein G-2 (gG-2, gG-2 antibodies) were determined by a double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and immunoblot analysis. We found that 40% of HIV+ and 23% of HIV- homosexual men were positive for the gG-2 antibodies, what is 3.6 and 2.1 times higher incidence, respectively, than that in the control heterosexual population (Bystrická et al., Acta Virol. 42, 319-324, 1998). Identification of individuals infected with genital herpes among HIV+ and HIV- homosexual men should be succeeded by antiviral therapy in order to prevent transmission of HSV-2 and HIV as well in this community.

Monoclonal antibodies suitable for type-specific identification of herpes simplex viruses by a rapid culture assay.

Eight monoclonal antibodies (MAbs) to herpes simplex viruses 1 and/or 2 (HSV-1, HSV-2) were tested for their reactivity with 190 previously typed HSV-positive clinical specimens in order to determine their suitability for use as type-specific reagents. Using a rapid culture assay we found that two MAbs (T51 and T96) identified HSV-1 in all the 94 specimens, previously found HSV-1-positive, but did not react with the 96 specimens, previously found HSV-2-positive. In contrast, one MAb (303) confirmed the presence of HSV-2 in all the specimens, previously found HSV-2-positive, but did not react with any of the 94 specimens, previously found HSV-1-positive. These three type-specific MAbs allow for a rapid type-specific identification of HSV in infected cultures. One type-common MAb (T111) reacted with all HSV-positive cultures. This MAb can be used as an excellent reagent for detection of HSV infection.

Antibody responses to the herpes simplex virus type 2 glycoprotein G in sera of human immunodeficiency virus-infected patients in Slovakia.

Thirty sera of human immunodeficiency virus-positive (HIV+) and 37 sera of HIV-negative (HIV-) individuals in Slovakia were tested for the presence of antibodies to herpes simplex virus type 2 (HSV-2) glycoprotein G (gG). A notable difference between the prevalence of HSV-2-specific antibodies in HIV+ and that in HIV- individuals was found (37% vs. 11%) confirming and extending previous reports that HSV-2 infection is an important risk factor for HIV transmission. Efforts toward the detection of HSV-2 infection and its therapy by anti-HSV drugs should be considered an important factor in decreasing the risk of contracting and spreading of HIV in Slovakia.

Monoclonal antibodies to the distinct antigenic sites on glycoproteins C and B and their protective abilities in herpes simplex virus infection.

The relative importance of the humoral immune response to various antigenic sites on the glycoproteins C and B (gC, gB) of herpes simplex virus (HSV) was evaluated in BALB/c and DBA/2 mice passively immunized with monoclonal antibodies (MoAbs) and then challenged with lethal dose of infectious virus. Eight MoAbs to three topographically distinct antigenic sites on gC and eight MoAbs to two distinct antigenic sites on gB were selected. The results indicated that any antigenic site on gC and gB contains epitopes for the protective immunity. However, individual MoAbs to different epitopes of the same antigenic site (i.e. antigenic site III on gC, and antigenic site II on gB) varied extremely in their protective ability. The protection did not correlate with the virus neutralization in vitro whereas it correlated significantly with the immune cytolysis in the presence of complement. The information about protective epitopes is essential for understanding the immunology of HSV infection at molecular level and may have implications for the design of HSV vaccine.

Herpes simplex virus type 2 and pseudorabies virus associated growth factors and their role in the latency in vitro.

A putative herpes simplex virus type 2 (HSV-2) growth factor (HSGF-2) was detected in a crude extract from virus infected mouse embryo cells. This factor, similar to previously described pseudorabies virus (PRV) associated growth factor (PRGF) was shown to have ability to morphologically transform non-transformed cells and to repress the transformed phenotype of transformed cells. Both activities could be neutralized with two, out of seven monoclonal antibodies directed against glycoprotein B of HSV-2. Both PRGF and HSGF-2 were detected in human embryo lung cells latently infected with PRV or HSV-2 either at 41 degrees C, or in the presence of phosphonoacetic acid. Human alpha-2 interferon, when present in medium of latently infected cells enhanced the production of both HSGF and PRGF. On the contrary, when latently infected cells were treated with 5-azacytidine the synthesis of both PRGF and HSGF-2 was completely blocked and the virus reactivated from latency replicated to higher titers than in non-treated cells. The role of PRGF and HSGF-2 in the establishment, maintenance and reactivation of latency, as well as in cellular transformation is discussed.

Type-common and type-specific monoclonal antibodies to herpes simplex virus types 1 and 2.

Seventeen monoclonal antibodies (Mabs) reacting specifically with the cells infected with herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2) were characterized by a variety of immunological tests such as radioimmunoprecipitation, immunoblotting and virus-neutralization. The majority of Mabs was directed against glycoprotein B (anti-gB), six reacted with glycoprotein C (anti-gC) and one with glycoprotein G (anti-gG). Six anti-gB Mabs reacted with both types of HSV (anti-gB-1,2), two anti-gB and all the six anti-gC Mabs have been specific for HSV-1 (anti-gB-1 and anti-gC-1). The remaining two anti-gB Mabs and the anti-gG have been specific to HSV-2 (anti-gB-2 and anti-gG). Only three out of the seventeen examined Mabs neutralized the virus.

Synthesis of glycoproteins of syncytial and non-syncytial strains of herpes simplex virus type 1 and their transport to the plasma membrane.

Underglycosylated form of glycoprotein C (gC) synthesized in the presence of tunicamycin was found on the surface membrane of BHK cells infected with the non-syncytial (non-syn) strain Kupka of herpes simplex virus type 1 (HSV-1). Such form of gC was not detected in the plasma membrane of tunicamycin-treated cells infected with the syncytial (syn) HSZP strain of HSV-1. In comparison to the non-syn strain Kupka, a smaller amount of glycoproteins of the syn HSZP strain was detected on the surface membrane of Vero cells. The same results were obtained using BHK cells, in which no polykaryocytes were induced. The individual glycoproteins of both strains under study had been synthesized and accumulated in a similar way in infected cells. However, at least in accumulated in a similar way in infected cells. However, at least in Vero cells a delay in the processing of syn strain HSZP glycoproteins was observed.

Liquid-phase and solid-phase radioimmunoassay with herpes simlex virus type 1 nucleocapsids.

Liquid-phase radioimmunoassay (LPRIA) and solid-phase radioimmunoassay (SPRIA) are described utilizing either 125I-labelled or immobilized nucleocapsids (NC) of herpes simplex virus type 1 (HSV-1). These techniques appeared sensitive and specific for quantification of HSV-NC antigens and corresponding antibodies.

Ultrastructural localization by immunoperoxidase techniques of influenza virus antigens in abortive infection of L cells.

An abortive infection was induced in L cells by influenza virus A/Hong Kong/68 (H3N2). With the use of antibody and peroxidase-labelled protein A, the localization of virus protein synthesis but not the maturation of virus particles was demonstrated at the ultrastructural level. Five days after inoculation (p.i.), the synthesis of viral haemagglutinin was localized in the region of the rough endoplasmic reticulum; at late intervals p.i., haemagglutinin accumulated in the plasma membranes, where membrane vesicles, containing haemagglutinin in their membranes, were released from the cell surface. The cytoplasmic viral ribonucleoprotein was localized in the region of free cytoplasmic ribosomes and that of the outer sheet of the nuclear membrane. Viral proteins were detected in the cytoplasm and plasma membranes also after 70 and 390 days of passaging of the cells or of their long-term cultivation with regular change of medium.

Detection of herpesvirus antigens by solid-phase radioimmunoassay with 125I-antiglobulin and 125I-protein A.

The binding of immune (IS) and non-immune (NS) sera to herpes simplex virus type 1- (HSV-1) infected Vero cells was tested by indirect solid-phase radioimmunoassay (RIA) with radioiodinated swine anti-rabbit IgG (125I-SwAR-IgG) or staphylococcal protein A (125I-SPA). To indicate the binding of non-immune IgG molecules to virus-induced Fc-receptors, the cells were incubated in the presence or absence of the glycosylation inhibitor 2-deoxy-D-glucose (DOG). With 125I-SwAR-IgG, the binding of both IS and NS to untreated cells was higher at all time intervals than their binding to infected cells kept post infection in the presence of DOG. The titre of IS as detected by 125I-SwAR-IgG remained unchanged regardless whether the cells were incubated in the presence or absence of the drug. 125I-SPA gave much higher net binding than 125I-SwAR-IgG but, the end point titre of IS as measured by 125I-SPA was 1-2 dilution steps lower than with 125I-SwAR-IgG.

[Preparation of porcine IgA and its detection using the fluorescent antibody technic]. / Príprava prasacieho IgA a jeho detekcia metódou fluorescencných protilatok

The preparation of immunoglobulin A (IgA) from porcine colostrum, intestinal content and serum is described. The best results were achieved with colostrum, from which an antigen of satisfactory purity was prepared by purification on Sephadex G-200, on DEAE cellulose and subsequent filtration on Sephadex G-200. The serum to this antigen raised in rabbits was adsorbed to an immunoadsorbent from porcine serum (PS) or porcine IgG. The adsorbtion of the serum against secretory IgA (SIgA) to PS removed its undesirable heterologous and nonspecific reactivity. The anti-SIgA serum adsorbed in this way still reacted with IgA from porcine serum. In the direct and indirect immunofluorescent staining we detected the main antigenic determinants of the SIgA molecule, i. e. the heavy chains and the secretory component.