The immunization of young healthy males with adsorbed staphylococcal toxoid revealed the existence of two main types of postimmunization humoral response. One of them was characterized by an early (on days 7-14 after immunization) rise in the titer of antibodies with the subsequent gradual decrease of their content, while the number of circulating T-suppressors remained unchanged. The characteristic feature of the other type was a slow rise in the level of antitoxins by day 21 after immunization with the subsequent drop of their titers, preceded by a considerable increase in the number of circulating T-suppressors. The maximum antibody titer was definitely higher in the first type of response than in the second type (14.8 +/- 1.41 and 9.0 +/- 1.53 I. U./ml respectively). A single plasmapheresis procedure on day 21 after immunization produced no essential effect on the dynamics of the characteristics of cell-mediated and humoral immunity.