Complications and immunological studies of measles virus infection in antithymocyte-treated hamsters

A study was done to investigate possible late central nervous system (CNS) complications of latent measles infection in hamsters. Signs of CNS disease, consisting of myoclonus and paralysis, occurred in some weanling hamsters inoculated intraperitoneally at 3 or 9 days of age with antithymocyte serum (ATS) and measles virus, but no late complications in adult life attributable to measles virus were seen. A single series of ATS injections plus an injection of measles virus resulted in sustained antibody formation postulated due to establishment of a latent viral infection, whereas similar treatment with normal rabbit serum plus virus caused no or minimal antibody response. The majority of hamsters receiving ATS as newborns and ATS plus virus as weanlings also did not produce antibody. This differential effect of ATS may be due to combined elimination of suppressor and helper cells in the latter ATS-treated group and of suppressor cells only in the former ATS-treated group. Cellular immunity could not be evaluated since lymphocytes from inoculated and uninoculated hamsters released equal and variable amounts of 51Cr for both infected and noninfected labeled, allogeneic hamster target cells.