T-CELL REGULATION OF HUMAN PERIPHERAL BLOOD B-CELL RESPONSIVENESS BY A N T H O N Y

J. S T R E L K A U S K A S , B A R R Y S. W I L S O N , * R I C H A R D LEONARD CHESS, AND S T U A R T F. S C H L O S S M A N

T. C A L L E R Y ,

(From the Sidney Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, and the Department of Microbiology, University of Illinois Medical Center, Chicago, Illinois 60612)

The interactions necessary for the generation of mature plasma cells from precursor B cells are not entirely understood, but evidence suggests that antigens, T cells, and macrophages are involved (1-7). It has become increasingly clear that T lymphocytes exert critmal regulatory control on the immune responses of B lymphocytes as well as other T lymphocytes (8). The signals originating from T cells and their products have been most extensively studied and the following points have emerged: (a) the cell interactions between T and B cells are genetically restricted by genes coded for, or closely linked to the major histocompatibility complex (MHC) of the species (9, 10) and (b) the influence of T cells may be of a positive (helper) (11) or negative (suppressor) (12) type. It is thought that T-cell regulation is most critical during both the induction of a primary, and in the elicitation of a secondary antibody response. At present, little evidence exists for a role of T cells in the regulation of synthesis of antibodies by more differentiated B cells or plasma cells. In the p r e s e n t studies, we h a v e i n v e s t i g a t e d t h e influence of T cells on the s p o n t a n e o u s s y n t h e s i s a n d secretion of Ig b y h u m a n p e r i p h e r a l blood B cells. A l t h o u g h the specificity of the i m m u n o g l o b u l i n s are u n k n o w n , B-cell production of Ig c a n be r e a d i l y detected b y a r e v e r s e h e m o l y t i c plaque t e c h n i q u e which detects Ig secretion t h r o u g h the use of anti-Ig-coated e r y t h r o c y t e s followed b y d e v e l o p m e n t w i t h c o m p l e m e n t . The e x p e r i m e n t s described below show that: (a) p e r i p h e r a l blood l y m p h o c y t e s contain cells which actively s y n t h e s i z e a n d secrete Ig; (b) highly purified B cells alone, in contrast, a r e less capable of secreting Ig t h a n u n f r a c t i o n a t e d lymphocytes; (c) m a x i m a l secretion of Ig b y B cells can be r e c o n s t i t u t e d by t h e addition of T cells; a n d (d) these TB i n t e r a c t i o n s a p p e a r to be influenced b y c o m p a t i b i l i t y a t t h e MHC.

Materials and Methods Mononuelear cells were isolated from the peripheral blood of normal volunteers by Ficoll-Hypaque density gradient centrifugation. These unfractionated cells were separated into surface Ig+ B cells and surface IgT-cell populations by methods previously described (13). Briefly, cells were passed over Sephadex G-200 columns which had been coupled with anti-human F(ab)2 antibodies. Cells which were surface Ig- passed through the column, whereas surface Ig+ cells were retained and subsequently Isolation of Purified T and B Cells from Human Peripheral Blood.

* Present address: Scripps Clinic and Research Foundation, La Jolla, Calif. ~Abbreviations used in this paper HBSS, Hanks' Balanced Salt Solution; M H C , histocompatibilitycomplex; PFC, plaque-forming cells.

major

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1765

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MEDICINE

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146, 1977

1766

H U M A N T- AND B-CELL COOPERATION

eluted with h u m a n g a m m a globulin. Both the Ig + and Ig- populations were analyzed by direct rosetting with h u m a n erythrocytes coated with anti-light-chain antibody (14). Ig + cells were shown to form a t least 95% rosettes, whereas Ig- populations had