CD77: an antigen of germinal center B cells entering apoptosis

Eur J Immunol. 1991 May;21(5):1131-40. doi: 10.1002/eji.1830210507.


We have previously reported that a neutral glycolipid (globotriosylceramide; Gb3) was specifically expressed on Burkitt's lymphoma cells and on a subset of germinal center tonsillar B lymphocytes. Recently the Gb3 molecule was recognized as a new B cell differentiation antigen and now defines the CD77 cluster. Here we report an extensive phenotypic and functional characterization of the tonsillar CD77+ B lymphocytes. These cells have a low buoyant density and are thus purified using a Percoll gradient. They express various B cell antigens such as CD19, CD20, CD21, CD22 and CD40, as well as the adhesion molecules LFA-1, LFA-3 and CD44. They are positive for surface IgM and negative for surface IgD. Although these results suggest a phenotype of activated B cells, the CD77+ cells are negative for the classical activation antigens: CD23 (the low-affinity Fc receptor for IgE), CD25 [the interleukin (IL) 2 receptor alpha chain] and CD71 (the transferrin receptor). Proliferation and protein synthesis of CD77+ cells was measured after stimulation with a range of mitogens and IL. None of the agents tested are able to induce proliferation and protein synthesis with the exception of a combination of recombinant IL 4 plus anti-CD40 antibody. When examined by electron microscopy, CD77+ B lymphocytes present a morphology similar to that of cells undergoing programmed cell death, also called apoptosis (i.e. chromatin condensation, nuclear fragmentation, membrane blebbing). As shown by direct examination of DNA, these CD77+ cells are indeed in the process of apoptosis. Treatment of the CD77+ cells by recombinant IL 4 and anti-CD40 antibody prevents apoptosis. All these results suggest that the CD77 molecule defines a B lymphocyte maturation pathway, specific for germinal center, where the cells undergo programmed cell death.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / immunology
  • Antigens, CD / physiology*
  • Antigens, Differentiation, B-Lymphocyte / physiology
  • B-Lymphocytes / immunology
  • B-Lymphocytes / physiology*
  • B-Lymphocytes / ultrastructure
  • CD40 Antigens
  • Cell Separation
  • Cell Survival
  • DNA / metabolism
  • Glycolipids / analysis
  • Humans
  • Lymphocyte Activation
  • Phenotype
  • Protein Biosynthesis
  • Receptors, Lymphocyte Homing / physiology
  • Trihexosylceramides / analysis
  • Trihexosylceramides / physiology*


  • Antibodies, Monoclonal
  • Antigens, CD
  • Antigens, Differentiation, B-Lymphocyte
  • CD40 Antigens
  • Glycolipids
  • Receptors, Lymphocyte Homing
  • Trihexosylceramides
  • globotriaosylceramide
  • DNA