Lymphocyte migration in inbred Syrian hamsters with acute measles virus encephalitis

The migratory pattern of 51Cr-labeled adult lymphocytes, as measured by 51Cr concentration in various tissues, was followed in inbred weanling Syrian hamsters infected intracranially with measles virus. Donor-labeled lymphocytes were inoculated intracardially into infected and control recipients. Increased passage of labeled lymphocytes across the blood-brain barrier was first seen on day 3 post virus inoculation and 1 day prior to development of clinical signs of acute measles encephalitis. 51Cr concentration in the brain increased progressively along with neurologic signs until the death of the hamsters. Aberration of lymphocyte migration peripherally, manifested by reduced presence of labeled cells in lymph nodes and spleen, first occurred 4 days post virus inoculation in those hamsters with clinical signs of disease. By days 5 and 6 post virus inoculation, the concentration of 51Cr in lymph nodes was 30% and 20%, respectively, of that in lymph nodes of control hamsters. Concentration of labeled lymphocytes in lymph nodes and spleen of the occasional virus-inoculated animal that appeared clinically well at time of autopsy was always greater than that in ill hamsters, and was closer to and sometimes equal to the concentration in the corresponding tissues of control hamsters. Thus, increased passage of labeled lymphocytes into the brain and decreased recovery of labeled lymphocytes in lymph nodes and spleen occurred concomitantly with increased neurologic signs of disease. No differences in presence of labeled cells in other tissues tested (liver, lung, thymus and blood) between infected and control hamsters were noted. Labeled lymphocytes from either measles virus or ovalbumin-immunized donors appeared to pass more readily into the brains of ill recipients than labeled lymphocytes from unimmunized donors.