Influence of nonsteroid anti-inflammatory drugs on lymphocyte subpopulation and on the primary humoral response in normothermic and feverish rabbits.

Rabbit peripheral blood was tested for the ratio of T and B lymphocytes and for the number of plaque forming cells (PFC) on day 5 and 6 after immunization with sheep erythrocytes. Fever was induced by intravenous injection of lipopolysaccharide (LPS) of E. coli. At higher doses, suppressing the fever, only indomethacin (40 mg/kg per day) inhibited the number of lymphocytes, subpopulation of B cells and their capability for hemolytic antibodies synthesis. This effect was not observed with indomethacin at five fold lower dose. Mefenamic acid (60 mg/kg per day) and acetylsalicylic acid (200-900 mg/kg per day) per se irrespectively of the dose applied, do not affect lymphocyte subpopulations and the primary humoral response. All the three drugs investigated counteracted with the changes in the number of B lymphocytes and PFC induced by LPS.