Immunoglobulin responses to echovirus type 11 by enzyme linked immunosorbent assay: single-serum diagnosis of acute infection by specific IgM antibody

Aloe polymannose enhances anti-coxsackievirus antibody titres in mice

Aloe polymannose (AP), a high mannose biological response modifier (BRM) purified from the Aloe barbadensis Miller plant, was tested for activity in enhancing antibody titres against coxsackievirus B3 (CVB3) and CVB3-induced myocarditis in murine models of the disease. Inoculation of mice with AP over a range of three nontoxic doses and in varying schedules did not reduce virus titres in heart tissues or ameliorate virus-induced cardiopathological alterations during acute disease. However, this BRM was found to significantly enhance titres of anti-CVB3 antibodies produced during acute infection of three strains of mice with CVB3. Simultaneous intraperitoneal inoculation of AP at a dose of 0.5 mg/kg body weight per mouse with purified CVB3 significantly increased ELISA titres of anti-CVB3 antibodies and the proportion of mice with these titres, compared with similar parameters in mice inoculated only with CVB3. The data conclusively show that AP can immunopotentiate antibody production against capsid protein epitopes of a nonenveloped picornavirus and suggest this BRM (AP) might be of benefit in enhancing antibody titres against other enteroviruses during a natural infection and poliovirus vaccine strains.

Transient erythroblastopenia of childhood presenting with echovirus 11 infection

We report a case of transient erythroblastopenia in a three-year-old girl presenting with echovirus 11 infection. Viral infection was demonstrated by isolation of echovirus 11 in stool cultures and the presence of echovirus 11-specific IgM antibody in serum. We suggest that echovirus may have played a role in the pathogenesis of transient erythroblastopenia of childhood in this patient.

Indirect ELISA for the detection of HSV-2 specific IgG and IgM antibodies with glycoprotein G (gG-2)

The glycoprotein G (gG-2) purified from HSV-2 infected cells has been reported to be useful for determination of HSV-2 type-specific antibodies using conventional ELISA formats. This study further confirmed the specificity of gG-2 and demonstrated the feasibility of a specific IgM assay. The gG-2 ELISA was developed to detect HSV-2 specific IgG and IgM antibodies in human sera with high levels of sensitivity and specificity. Of 45 patients with culture-proven recurrent HSV-2 genital infection 44 were reactive for gG-2 IgG. Of 30 sera from patients with culture-proven recent initial HSV-2 genital infection 29 were positive for gG-2 IgM. Three patients with primary HSV-2 genital infection showed gG-2 IgM in the convalescent but not in the acute sera. The IgG- and IgM-gG-2 ELISA showed high specificity. None of 40 sera from children were reactive by either assay. Only one of 94 sera from patients with antibody to herpesviruses other than HSV reacted in the IgG assay but none reacted in the IgM assay. There was no cross-reaction with sera from patients with proven HSV-1 infection with the gG-2 antigen. The results suggest that the IgG assay can be used for demonstration of past HSV-2 infection and the IgM assay for the diagnosis of HSV-2 in neonatal herpes and primary genital herpes, when cultures or rapid diagnostic techniques are unavailable.

Detection of immunoglobulin G, M, and A antibodies to enterovirus structural proteins by immunoblot technique in echovirus type 4-infected patients

Paired serum specimens from 24 patients with echovirus (EV) type 4 infection by virus isolation were tested by the immunoblot technique for the presence of IgG, IgM, and IgA antibodies to EV4 structural proteins. Single sera from 20 patients without neutralizing enterovirus IgM were used as controls. All the sera from EV4-infected patients had IgG antibodies to VP1 of EV4 but also 13 out of the 20 controls. 23 out of 24 EV4-infected patients elicited IgM and IgA specific antibodies to VP1, a pattern highly significant as compared with controls (3/20 for IgM and 8/20 for IgA). In 16 out of the 24 EV4-infected patients, the IgM antibodies were also directed against VP2 (versus 2 out of 20 in the control group). Anti-VP2 IgA were detected in 4 out of the 24 EV4 patients (versus 0 in controls). The 24 paired sera from EV4-infected subjects were also tested by immunoblot technique against three other enteroviruses: EV21, coxsackievirus A9 and poliovirus 1. Cross-reactivities were observed to a large extent against VP1 and VP2 proteins with the three classes of antibodies. These results confirm the data of previous studies on the reactivity of IgM antibodies to various structural proteins that IgG antibodies react exclusively to VP1. Furthermore, this study demonstrates the occurrence of circulating IgA antibodies directed to VP1 and sometimes VP2 in the course of enterovirus infection. The potential interest of this latter finding for diagnosis requires further investigation.

Rapid diagnosis of echovirus 33 infection by neutralizing specific IgM antibody

In 1982, we isolated 20 strains of echovirus type 33 (EV33) from 18 patients. We studied the humoral response to EV33 of 2,437 subjects from whom at least one serum was available during the same year. In 388 subjects with the neutralizing antibody level at 64 or more, we assayed the EV33 IgM antibodies by seroneutralization test after fractionation of sera by ion exchange chromatography. One hundred ninety-five subjects (8.0%) had a high titre (greater than or equal to 32) of EV33 IgM antibodies, which was considered as evidence of recent infection. The EV33-positive IgM fractions were assayed against five other enteroviruses. Sixty percent of the IgM fractions did not cross-react with any of the five serotypes, 8.7% cross-reacted with at least one serotype but with predominant EV33 IgM response, and 31.3% had an equivalent or greater amount of non-EV33 IgM antibodies; the type specificity of the assay was directly related to the age of the subjects. These findings suggest that determination of neutralizing specific IgM antibody is a sensitive and rapid test for the diagnosis of enterovirus infections, especially in young people.