Detection of immunoglobulin M antibodies to glycoprotein G-2 by western blot (immunoblot) for diagnosis of initial herpes simplex virus type 2 genital infections

Western blots (immunoblots) for the detection of immunoglobulin M (IgM) antibodies specific for herpes simplex virus type 1 (HSV-1) and HSV-2 in patients' sera were developed. The locations of the type-specific glycoprotein G (gpG-2) of HSV-2 (92- and 140-kDa forms) and glycoprotein C of HSV-1 (gpC-1), which carries mostly type-specific antigenic epitopes, were checked with specific monoclonal antibodies. Western blot assays for IgM antibody to gpC-1 or gpG-2 were performed after depletion of IgG by precipitation with anti-human IgG. In patients with primary HSV-2 genital infections, seroconversion of IgM and IgG antibodies to both the 92- and 140-kDa forms of gpG-2 was observed, although both antibodies appeared in convalescent-phase serum after the first week. IgM and IgG antibodies to low-molecular-size polypeptides (40 to 65 kDa) were the first antibodies observed in patients with primary infection, but these antibodies were cross-reactive with HSV-1 and HSV-2. However, in patients with recurrent HSV-2 infections, IgG antibodies to both forms of gpG-2 and the low-molecular-size polypeptides were found no matter how early after onset the patient was bled, and IgM to gpG-2 did not appear. In patients with nonprimary initial genital HSV-2 infections, IgG antibody to HSV-1 was demonstrated in the first serum specimen, and HSV-2-specific IgM was found in 39% of the serum specimens. Hence, the Western blot assay can be used to test for IgM antibody to gpG-2, allowing for the retrospective diagnosis of inital HSV-2 infections and its use as a supplementary test to the gpG-2 IgG enzyme-linked immunosorbent assays developed elsewhere. In contrast, IgM antibody to gpG-2 is not usually detected in patients with recurrent HSV-2 infections.

Effect of heparin on hemagglutinin of herpes simplex virus type 1

Heparin inhibited the hemagglutinin activity of herpes simplex virus (HSV) type 1. The minimal inhibitory concentration of heparin required to inhibit 8 hemagglutination (HA) U of HSV ranged from 0.005 to 0.01 U/ml. Mouse erythrocytes failed to combine with the HA inhibitory factor of heparin. On the other hand, mouse erythrocytes treated with heparinase had greatly reduced agglutinability by HSV. Virus-heparin complex formation was observed by sedimenting heparin with the virus particles.

[The use of immunostimulants for enhancing the immunogenicity of a herpes vaccine]

National immunostimulators and interferon inducers (poludan, ridostin, larifan, myelopide, vegetan) in combination with a commercial herpes vaccine (HV) were used for experimental immunization of mice. A 3-fold or greater rise of specific antibody titres was observed after a single immunization of intact BALB/c mice. In experiments in chronically infected animals a single inoculation of HV resulted in a 3-fold rise of specific antibody titres at 6 days postimmunization but not in later periods (20, 30 days). Administration of larifan, an interferon inducer, but not the immunostimulator myelopide, induced a synergic effect in these experiments. Activation of alpha-interferon production was observed early after combined use of HV and immunostimulators. It is concluded that combined experimental use of HV and immunostimulators activated both specific antibody production and interferon production.

Direct contact with herpes simplex virus-infected cells results in inhibition of lymphokine-activated killer cells because of cell-to-cell spread of virus

Natural killer (NK) and lymphokine-activated killer (LAK) cells are disarmed after contact with herpes simplex virus (HSV)-infected cells. Cells infected with HSV-1 mutants that lack glycoproteins essential for viral entry into cells (gB, gD, gK, gH, and gL) did not inhibit LAK cells; cells infected with HSV-1 mutants that lack glycoproteins not required for virus entry into cells (gE, gI, gG, and gJ) inhibited lysis. LAK cells became infected after contact with target cells infected with wild-type HSV-1 but not with a gD-HSV-1, which cannot spread from cell to cell. Because LAK cells were inhibited only by very high concentrations of cell-free preparations of HSV and because neutralizing antibodies did not prevent infection of LAK cells in contact with infected cells, infection of LAK cells is probably greatly enhanced by the apposition of the effector and target cell membranes during target recognition. Disarming of immune effector cells by infection may be a general strategy for immune evasion by HSV.

[Detection of herpes simplex virus 1 and 2 (HSV-1 and HSV-2) IgG and IgM by ELISA in cord blood and sera of mothers with pregnancy complications]

In this study, HSV-1 IgG, IgM and HSV-2 IgG, IgM antibodies by ELISA in the sera of the mothers who had different kinds of obstetrical problems like abortus, stillbirth, prematurity, postmaturity, intrauterine development retardation and in the newborns' cord sera who had congenital anomalies like anencephaly, cataract and dolichocephaly were investigated. In these mothers HSV-1 IgG positivity ratio was 71/73 (97.3%). There was no significant difference in the age group distribution of HSV-1 IgG. The HSV-1 IgG positivity ratios in mother sera were the same as in cord sera. It was found that HSV-1 IgG antibodies passed transplacentally. It was established that one of the subjects had premature baby and the other had stillbirth inspite of HSV-1 IgG negativity but in the risk group subjects. HSV-1 IgM was found positive in 7 mothers (9.6%) of the study group. This data was the sign of active or reactive infection. There were 3 abortus, 1 stillbirth and 3 anomalous baby in HSV-1 IgM seropositive mothers. In these mothers, 65/73 (89%) HSV-2 IgG and 6/73 (8%) HSV-2 IgM seropositivity were defined. In the cord sera these ratios were 65/73 (89%) and 2/73 (2.7%). IgM seropositivity of the material of the mothers who had abortus was explained by the effect of HSV-2 activity and the presence of HSV-2 IgM, 4 mothers were noted for the active or reactive infection sign. It was understood that HSV-2 IgG passed completely via placenta and there were no significant difference between the presence of the antibody and the age group.

An assay method for herpes simplex virus type 1 seroprevalence survey--detection of antibody in saliva by avidin-biotin complex enzyme-linked immunosorbent assay (ABC-ELISA)

To determine whether the avidin-biotin complex enzyme-linked immunosorbent assay (ABC-E) is a potentially useful method for detection of herpes simplex virus type 1 (HSV-1) antibody in saliva, paired serum and saliva samples from 129 healthy individuals aged 18 to 25 years were collected simultaneously and subjected to a neutralization test (NT) for neutralizing antibody and also to an indirect ELISA (IE) and ABC-E for HSV-1 specific IgG detection. Compared with the results of NT, the sensitivities of the IE and ABC-E for serum were both 100% (45/45), and for saliva 82.2% (37/45) and 93.3% (42/45), respectively. The specificity of all these methods was 100% (84/84). With the same ABC-E method, a significant correlation (r = 0.66, P < 0.001) between the OD-difference (d-OD) values of positive serum and saliva samples was observed. Furthermore, the consistency of ABC-E for salivary antibody detection was confirmed with the paired serum and saliva samples which were collected from four individuals followed up for eight months. It was clear that the ABC-E method for saliva can be used in place of the NT and ABC-E method for serum for seroprevalence studying of HSV-1 infection.

Monoclonal anti-idiotypes to herpes simplex virus type 1 capable of antigen specific priming & stimulatory activity

Anti-idiotypic antibodies (Ab-2) to HSV-1 (herpes simplex virus 1) neutralizing monoclonal antibody were raised by hybridoma. These Ab-2 were found to represent an epitope of glycoprotein B (gB-1) of this virus. To further characterise this antibody for its ability to mimic the antigenic epitope, in vitro lymphoproliferation assays were done. In this assay (i) antigen specific lymphocyte priming activity of the three monoclonal Ab-2 and (ii) the in vitro stimulating ability of these Ab-2 for gb-1 primed mouse lymphocytes were tested. We could identify two monoclonal Ab-2 which were able to prime the mouse lymphocytes in vivo. These antibodies were able to recognise the in vitro stimulation signal of the antigen gB-1 and consequently could proliferate. The stimulation index was comparable to that with the antigen. These two Ab-2 were also recognized by the antigen primed mouse lymphocytes in a specific manner.

Monoclonal anti-idiotype antibody to HSV-1 neutralizing monoclonal antibody: production and characterization

This study is an attempt to produce and characterize murine monoclonal antibodies directed against the paratope of HSV-1 neutralizing monoclonal antibody. Monoclonal antibody 138 C5G10 which was neutralising and directed to 120 K antigen gB of HSV-1 was used as the idiotype. We were able to produce three Ab-2 monoclonal antibodies as characterized using immunofluorescence, ELISA and RIA. The findings of the present study suggest that two antiidiotypes 3AiB3E10 and 3AiB5D10 share the same unique fine specificity while 3AiB3C9 has a different specificity on 138 C5G10 paratope. The utility of such 'surrogate' antigens in serological assays and modulation of immune response is discussed.

Flow cytometric indirect immunofluorescence assay with high sensitivity and specificity for the detection of antibodies to HSV-1 and HSV-2

Cells infected with HSV-1 or HSV-2 develop viral antigens which can be detected by immunofluorescence. We developed a flow cytometric indirect immunofluorescence assay to detect and quantitate antibodies to HSV-1 and HSV-2 in human sera. Results obtained by flow cytometry for detecting antibodies against HSV-1, when compared with results obtained by ELISA, showed an index of overall agreement of 100%. The correlation between the antibody titers obtained with each method was found to be highly significant. An index of overall agreement equal to 94.1% was observed between results obtained by flow cytometry and by immunofluorescence as concerns the discrimination of HSV-2 positive from negative samples. However, the correlation between antibody titers was found to be not statistically significant. The flow cytometric assay proved to be type-specific.

Underestimation of HSV-2 seroprevalence in a high-risk population by microneutralization assay

BACKGROUND

Complement independent neutralizing antibody assays (CINA) have been used in seroepidemiologic studies and in diagnostic laboratories to distinguish between antibodies to herpes simplex virus types 1 (HSV-1) and 2 (HSV-2). The accuracy of CINA has not been rigorously tested against protein-specific typing assays, such as Western blot.

GOAL OF THIS STUDY

To determine the ability of CINA to identify HSV-2 antibodies alone or in the presence of HSV-1 antibodies.

STUDY DESIGN

Sera from randomly selected women at the Seattle King County Sexually Transmitted Disease Clinic were tested by CINA and Western blot.

RESULTS

Of 521 women tested, 81% had HSV antibodies by Western blot and 76% had neutralizing antibodies. Of 220 sera with HSV-2 antibodies by Western blot, 106 (48%) were serotyped correctly by CINA. Of the women studied, 140 (27%) had type-indeterminate neutralizing antibodies; 55 of these sera (39%) had antibody only to HSV-1 by Western blot.

CONCLUSION

The seroprevalence of HSV-2 in an STD clinic population was seriously underestimated by CINA.

Murine herpes simplex virus keratitis is accentuated by CD4+, V beta 8.2+ Th2 T cells

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Herpes simplex type 1-induced Fc receptor binds to the Cgamma2-Cgamma3 interface region of IgG in the area that binds staphylococcal protein A

The binding site of immunoglobulin G (IgG) to herpes simplex virus (HSV) type 1-induced Fc receptor was investigated using human IgG Fc intermediate (Fc(i)) fragments, fragment D of staphylococcal protein A (SPA) and chemically modified human IgG. Human IgG Fc(i) fragment composed of one Cgamma2 and two Cgamma3 domains, bound strongly to HSV-1-infected cells. Fragment D, a monovalent subunit of SPA, inhibited the binding of radiolabelled human IgG Fc fragments to the HSV Fc receptor. Reductively methylated human IgG reacted equally well to HSV-infected cells, as did chemically unmodified IgG in contrast to N-acetylimidazole-modified and diethylpyrocarbonate-modifed human IgG, which were unreactive. These results suggest a similar binding site on human IgG for SPA and the HSV-1 Fc receptor with involvement of the amino acid residues Tyr and His but not Lys. The similarities of binding sites on the IgG molecule for the HSV-1 Fc receptor and rheumatoid factors (RF) may be important for understanding the mechanism of RF production in rheumatoid arthritis or other disease states.

Functional cross-reactivity between the glycoprotein B of herpes simplex virus type 1 and Epstein-Barr virus

A monoclonal antibody (T157) directed against gB-1, the glycoprotein B (gB) of herpes simplex virus-1 (HSV-1) shows positive indirect immunoflourescent staining with an Epstein-Barr virus (EBV)-transformed lymphoblastoid cell line B95-8. SDS PAGE and Western blot analysis show that B95-8 cells contain a 110,000 MW protein that co-migrates with the 110,000-115,000 MW gB-1. The gB-1 homologue of EBV (gB-EBV), immunopurified using a T157 affinity column, cross-stimulates HSV-1 immune T cells to proliferate in vitro. Mice immunized by a single subcutaneous injection of 30 microg gB-EBV in saline developed significant protection against HSV-1 challenge infection. Therefore gB-EBV can be considered a potential candidate vaccine and as an antigen to examine the cell-mediated immune response mounted by the host to limit virus spread during productive infection. The significance of a better understanding of the immune response to this and other EBV proteins of productive infection as an alternative to limit tumour growth by preventing virus spread is discussed.