Class-specific antibody titres (ELISA) against the primary immunogen Helix pomatia haemocyanin (HPH) in man

Using the indirect ELISA technique, IgM, IgG and IgA antibody titres against the primary test immunogen Helix pomatia haemocyanin (HPH) could be measured. All twenty-seven normal volunteers (age range 26-74 years) developed maximal or high IgM, IgG and IgA antibody titres 2 weeks after primary immunization with 1.0 mg HPH subcutaneously. Lower dose immunization resulted in submaximal responses. Titre kinetics in the three Ig classes correlated in height and time per person. There was no significant difference in antibody response between two adult age groups. Secondary immunization after 6 weeks, again with 1.0 mg HPH, when high titres were still present, resulted in a small titre increase in all three Ig classes. Comparison with the tanned red cell agglutination technique used previously, in combination with the 2-mercaptoethanol treatment of sera, showed the unreliability of 7S titres measured thus early in the primary immune response. Investigation of four patients with humoral immunodeficiency confirmed the class specificity of the test.