Differentiating owl monkey T and B lymphocytes by rosette formation.

Subpopulations of Aotus trivirgatus lymphocytes can be differentiated by the technique of rosette formation. Owl monkey B cells can be identified by erythrocyte-antibody-complement (EAC) rosette formation, since over 90% of EAC rosette-forming cells (RFC) have detectable surface immunoglobulins. A separate population of Aotus lymphocytes forms rosettes directly with sheep erythrocytes (E rosettes) and appears to be thymus-dependent (T cells) because (1) E rosette formation is blocked by anti-thymus serum, (2) over 80% of owl monkey thymocytes form E rosettes, and (3) most E RFC lack detectable surface immunoglobulins.