Studies of circulating T lymphocytes in marmoset monkeys (Saguinus fuscicollis) experimentally infected with non B human hepatitis

To ascertain the effect of viral hepatitis on the thymus dependent (T) lymphocyte population, percentages and absolute numbers of circulating T lymphocytes in marmosets experimentally infected with non B human hepatitis were measured. Four marmosets inoculated intramuscularly with GB strain of hepatitis virus and 4 uninoculated controls were monitored fortnightly for liver histology and weekly over a 4 month post inoculation (PI) period for serum enzyme activity (SGOT/SGPT) and for percentages and absolute numbers of ciculating T lymphocytes (spontaneous rosette formation with sheep erythrocytes (RFC)). All inoculated animals developed enzymatic and morphologic evidence of hepatitis 14-21 days PI that persisted for 2-3 weeks; percentages of RFC decreased from 60-65% during preinoculation and incubation periods to 35-40% during the acute phase of disease and then returned to normal levels (60-65%) by 5 weeks PI. Absolute numbers of circulating T lymphocytes were relatively consistent during the incubation and convalescent phases but decreased 29-45% during the acute phase of hepatitis. In uninoculated controls percentages and absolute numbers of RFC remained within normal ranges throughout the observation period.