Clonal expansion and differentiation of B lymphocytes are essential for the maintainance of the humoral arm of host defense. We propose a model for B cell growth whereby the role of ion channels in the regulation of expansion can be studied. In this system resting B cells become responsive to the growth promoting activity of anti-Ig if precultured in the presence of B cell stimulting factor-1 (BSF-1). This model predicts that B cells precultured with BSF-1 (phase-1) become """"""""competent"""""""" to proliferate in response to anti-Ig (phase 2). The role of ion channels in each phase of activation will be determined. To enhance our understanding of the molecular events that trigger B lymphocyte progression through the cell cycle, we propose to study mIg and BSF-1-mediated generation and modulation of transmembrane currents in single resting B lymphocytes. Using the patch clamp technique voltage sensitivity, ion selectivity and agonist activation of single ion channels will be determined. A profile of membrane channel properties will be obtained from determinations of channel distribution, mean channel lifetime and reversal potentials in response to membrane voltages clamped at specific levels and in response to BSF-1 +/-antiIg. To support and extend the electrophysiological studies, the function of these ion channels in the growth of B lymphocytes will be investigated by the use of specific in channel blockers. In addition to defining ion channel-receptor coupling, evidence for co-redistribution of membrane receptors and ion channels will be sought by patch clamping """"""""capped"""""""" regions of the B cell surface. The existence and nature of second messengers which regulate the activity of single channel events will be determined by a novel application of patch clamp technology. Coupling of mIgM and mIgD to specific ion channels will be determined using monoclonal anti-isotype specific antibodies. By comparing ion channel currents induced by anti-IgM in neonatal and mature B cell membranes, mechanisms for B cell tolerance vs activation may be revealed. Using well-defined mAb's to stage B cell ontogency, the ontogenic development of ion conductance systems in B cells will be defined. Through these approaches we combine the resources and expertise of eletrobiology and cellular immunology to pioneer new areas of exploration into the mechanisms of receptor-mediated cellular events.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM037767-02
Application #
3293457
Study Section
Immunobiology Study Section (IMB)
Project Start
1986-12-01
Project End
1989-11-30
Budget Start
1987-12-01
Budget End
1988-11-30
Support Year
2
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Dartmouth College
Department
Type
Schools of Medicine
DUNS #
041027822
City
Hanover
State
NH
Country
United States
Zip Code
03755
Noelle, R J; Roy, M; Shepherd, D M et al. (1992) A 39-kDa protein on activated helper T cells binds CD40 and transduces the signal for cognate activation of B cells. Proc Natl Acad Sci U S A 89:6550-4
Noelle, R J; Shepherd, D M; Fell, H P (1992) Cognate interaction between T helper cells and B cells. VII. Role of contact and lymphokines in the expression of germ-line and mature gamma 1 transcripts. J Immunol 149:1164-9
Noelle, R J; Marshall, L; Roy, M et al. (1992) Role of contact and soluble factors in the growth and differentiation of B cells by helper T cells. Adv Exp Med Biol 323:131-8
McCann, F V; McCarthy, D C; Noelle, R J (1991) Interleukin-4 activates ion channels in B lymphocytes. Cell Signal 3:483-90
Noelle, R J; Daum, J; Bartlett, W C et al. (1991) Cognate interactions between helper T cells and B cells. V. Reconstitution of T helper cell function using purified plasma membranes from activated Th1 and Th2 T helper cells and lymphokines. J Immunol 146:1118-24
Bartlett, W C; Purchio, A; Fell, H P et al. (1991) Cognate interactions between helper T cells and B cells. VI. TGF-beta inhibits B cell activation and antigen-specific, physical interactions between Th and B cells. Lymphokine Cytokine Res 10:177-83
Bartlett, W C; McCann, J; Shepherd, D M et al. (1990) Cognate interactions between helper T cells and B cells. IV. Requirements for the expression of effector phase activity by helper T cells. J Immunol 145:3956-62
McCann, F V; McCarthy, D C; Noelle, R J (1990) Patch-clamp profile of ion channels in resting murine B lymphocytes. J Membr Biol 114:175-88
Albrecht, D L; Mills, J W; Noelle, R J (1990) Membrane Ig-cytoskeletal interactions. III. Receptor cross-linking results in the formation of extensive filamentous arrays of vimentin. J Immunol 144:3251-6
Noelle, R J; Snow, E C (1990) Cognate interactions between helper T cells and B cells. Immunol Today 11:361-8

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