Neutralizing antibody and lymphocyte-mediated, colony-forming inhibition responses to measles infection in Cercopithecus aethiops monkeys.

The relation between humoral and cellular immune responses to measles virus in Cercopithecus aethiops monkedy was examined by in vitro virus neutralization and colony inhibition techniques. Both types of specific immune response were maximal two or three weeks after infection and then declined at similar rates for several weeks. However, the humoral response persisted at a low level for at least 44 weeks, whereas the cell-mediated response became undetectable as early as 10 weeks after infection. The cellular response disappeared in three monkeys (including one monkey that produced no detectable circulating antibody) after natural infection as well. Second inoculations with measles virus produced a rise in titer of antibody, but the cellular response was weak or lacking. However, there appeared to be a significant increase in the capacity of lymphocytes from these animals to attach in vitro to measles virus-infected cells. Antiserum to measles virus blocked this phenomenon.