Fecal IgA antibody responses after oral poliovirus vaccination in infants and elder children

We investigated fecal IgA antibody responses after oral polyvalent poliovirus vaccination. Infants were given vaccines twice with an interval of 6 weeks. Specific IgA antibodies in the feces were determined by enzyme-linked immunosorbent assay, and viruses were isolated in tissue cultures. We found that, after the first vaccination, antibody responses seemed to be elicited only against the serotypes of isolated viruses. After the second vaccination, however, antibodies were detected to all three serotypes with higher titers, suggesting that the first vaccination induced the immunologic memory. The IgA antibodies had virus-neutralizing activity, and existed in the feces as both intact 11S and fragmented 4S molecules. Next, children were given the third vaccination 3 or 9 years later. Fecal IgA antibody responses were found to be poorer in elder children, while they responded with high serum neutralization titers. The secretory IgA memory seemed to last much shorter the serum IgG memory.

Identification of group A coxsackieviruses by immune adherence hemagglutination

We investigated to find whether the immune adherence hemagglutination (IAHA) test could be used for identification of group A coxsackieviruses (Cox. A). By using homogenate of suckling mouse torsos infected with each of nine prototype viruses (Cox. A 2, 3, 4, 5, 6, 8, 9, 10 and 16) and 46 isolates as antigens and hyperimmune mouse ascitic fluids to the prototype viruses, we compared IAHA with complement fixation (CF) for serotyping of these viruses. The results of identification tests by IAHA were the same as those by combined use of CF and neutralization tests on all the 46 strains. By CF alone, however, six of 46 strains were not identified because of lower antigen titers; IAHA antigen titers were generally higher by 16-fold or more than CF tests. Furthermore, IAHA had a higher type-specificity than CF; a weak cross-reaction was found by IAHA only between Cox. A 3 and Cox. A 8. Nonspecific reactions encountered in IAHA were reduced more readily by kaolin than fluorocarbon treatment of the torso homogenates. From these results, we conclude that IAHA is an alternative method to CF and neutralization for serotyping of Cox. A viruses.