The role of membrane association of antigens in induction of cell-mediated immunity to viruses.

Infection with viruses which bud off cell membranes (e.g. herpes, myxoviruses) is known to induce cell-mediated immunity (CMI). There is less information about the ability of non-membrane-associated, lytic viruses (e.g. picornaviruses) to induce CMI. The purpose of this study was to compare CMI to mumps (a membrane-associated virus) and polio (non-membrane-associated virus) in man, employing two parameters: (a) a lymphocyte transformation assay [stimulation of tritiated thymidine ([H]TdR) uptake], and (b) immune interferon production. Twenty-three subjects were studied; twenty-two had positive mumps skin test; all had history of polio immunizations and fourteen had a live vaccine booster within 4 years of the study. Stimulants included phytohaemagglutinin (PHA) as a positive control, u.v.-inactivated mumps and polio type II antigens. The stimulation index (SI) was derived from (stimulated ct/min)÷ (unstimulated ct/min). PHA produced high SI and induced interferon; mumps antigen did not in the skin test-negative subject. All subjects with positive mumps test had significant (≥3) SI to mumps antigen; only seven subjects had an SI greater than or equal to 3 to polio antigen. The interferon response to mumps antigen was present in ten out of eleven skin test-positive subjects and to polio antigen in one out of twelve. It is concluded that CMI response is less constant and of lower magnitude following infection or immunization with non-membrane-associated viruses such as polio. This supports other data that antigens with a large surface area are more efficient in stimulating T lymphocytes and eliciting CMI.