Functional and structural characterization of immunoglobulin on murine B lymphoctes

Conference · Sat Jan 01 04:00:00 EST 1977 · Cold Spring Harbor Symp. Quant. Biol.; (United States)

OSTI ID:5113166

Parkhouse, R M.E.; Abney, E R; Bourgois, A; Willcox, H N.A.

Evidence for a structural homology between human IgD and its presumed mouse counterpart has been provided by the remarkably similar profiles of fragments resulting from tryptic digestion of the human and mouse proteins. More definitive homology awaits sequence determination. The memory cells of two antibody-forming cell clones had receptors of the IgM class, even though the clones had been producing IgG1 or IgG2a anti-DNP antibodies for 9 to 15 months previously (on antigenic stimulation). Thus a phenotypic switch in heavy-chain constant region evidently occurred after reexposure of these memory cells to antigen. These conclusions were drawn because removal of IgM, but not IgG or IgD, from the memory-cell population inhibited antigen recognition and subsequent differentiation to IgG-secreting cells. Thus surface IgM cannot be solely responsible for tolerance induction; neither can IgD be the unique triggering receptor for antigen on memory B cells. Instead, there may be a heterogeneity of Ig receptors on memory (and other) B lymphocytes which reflects the presence of subpopulations arising in the presence and absence of antigenic selection. Preliminary evidence does suggest that the immediate precursors of IgG-bearing cells may express either IgM or IgD. Thus IgG expression can occur independently of IgD, which would be in accord with our finding that at least some memory B cells recognize antigen via surface IgM. The details of the control and evolution of Ig expression remain to be elucidated, as does a defined role for IgD. The cells which bear IgD, however, are certainly derived from IgM-positive precursor lymphocytes, and the high frequency of lymphocytes expressing two Ig classes has profound implications for the mechanism of V-C gene integration.

• Research Organization: National Inst. for Medical Research, London
• OSTI ID: 5113166
• Conference Information: Journal Name: Cold Spring Harbor Symp. Quant. Biol.; (United States) Journal Volume: 41
• Country of Publication: United States
• Language: English

Related Subjects

550300 -- Cytology
551000* -- Physiological Systems
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMALS
ANTIGENS
BIOLOGICAL FUNCTIONS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CLONING
CONNECTIVE TISSUE CELLS
GLOBULINS
IMMUNE REACTIONS
IMMUNOGLOBULINS
LEUKOCYTES
LYMPHOCYTES
MAMMALS
MICE
ORGANIC COMPOUNDS
PHENOTYPE
PROTEINS
RODENTS
SOMATIC CELLS
TOLERANCE
VERTEBRATES