The only test so far introduced in a cell culture system for the determination of neutralizing antibody to human Coronavirus OC43 is based upon a neutralization-hemadsorption procedure, which does not seem to be reliable enough, since OC43-infected cell cultures do not present a true hemadsorption, but only a false hemadsorption or pseudohemadsorption. Using a cell culture-adapted strain of Coronavirus OC43, a microneutralization (MN) test was set up. Based upon determination of the hemagglutinating activity of the virus, the test gives results as early as 24 h after inoculation of cell cultures with virus-serum mixtures. Three groups of sera (from leukemic, non-leukemic children and adults) have been examined for antibody determination. Furthermore, 104 paired sera from the same groups of subjects have been tested for diagnosis of OC43 infection (or reinfection). Results have been compared with those obtained by hemagglutination-inhibition (HAI), using a cell culture prepared antigen, and the indirect immunoperoxidase antibody technique (IPA). The MN test appears to detect a slightly lower number of positive sera compared to the other two tests. However, it appears much more sensitive in detecting seroconversions (20 cases versus 10 detected by HAI and 16 by IPA). In 16 cases of seroconversion in children, the MN titer in the first serum was consistently ≤1:20. However, in adults seroconversion was observed in three cases with an initial MN antibody titer of 1:80. Neutralizing antibody, when present at a low titer, does not protect against reinfections. The new MN test offers a significant addition to techniques now available for serological diagnosis of human coronavirus OC43 infections.
|Number of pages||14|
|Publication status||Published - 1979|
ASJC Scopus subject areas
- Applied Microbiology and Biotechnology