Enumeration of t rosette-forming cell population in rabbit peripheral blood using human, sheep, guinea-pig, rat, mouse and chicken red blood cells under different experimental conditions.

Attempts were made to estimate peripheral T-lymphocytes in rabbits by their ability to form rosettes with sheep, human, guinea-pig, rat, mouse and chicken RBC. The reaction was studied under different conditions of pH and temperature. The test was also carried out in the presence or absence of glutaraldehyde. With sheep RBC, lymphocytes from 2 of the 5 rabbits studied formed rosettes to the extent of 1.5% in the system containing glutaraldehyde. These results however were not reproducible when studied after a week. The RBCs from other species, under similar experimental conditions, did not give rise to rosettes. The test carried out at pH 6.8 and pH 7.2 showed up to 4 and 8% rosettes respectively with rat RBCs, while RBCs of no other species showed rosettes. When rabbit lymphocytes preincubated at 37 degrees C for 1 h were used for rosette test with guinea-pig RBC, a maximum of 14.6% rosettes were obtained. Here, again the percentage of rosettes formed in the 5 animals, over a period of one month, varied widely. The reasons for the variations of the percentage of rosettes formed are discussed.