Broad antigenic relationships among rhinovirus serotypes revealed by cross-immunization of rabbits with different serotypes.

The rhinoviruses are a large group of at least 89 serotypes and extensive cross-relationships have been demonstrated among these serotypes using both rabbit and human antisera. The extent of these cross-relationships was further investigated by sequential intravenous immunization of rabbits with different virus serotypes, known to be both related and unrelated. In all cases in which a relationship had previously been demonstrated with monovalent antiserum, after heterotypic stimulation with the related virus, the antibody titer to the virus used as primary immunogen showed an anamnestic response, whereas the antibody response to the secondary immunogen was good, but resembled a primary response. In some instances when immunized rabbits were injected with an unrelated antigen, previously unsuspected relationships were revealed. A number of clusters of related rhinoviruses were demonstrated: 5, 17, 42; 3, 4, 6, 14; 9, 32, 67; and 13, 14, 41. Heterotypic immunization proved to be a powerful biologic probe for detecting relationships among the rhinoviruses, and together with newly available epidemiologic data it offers a possible approach for design of a vaccine for the common cold.