Role of I-A molecules in early stages of B cell maturation

J Immunol. 1992 Aug 1;149(3):801-7.


The role of the Ia molecule in the early phase of B cell development remains controversial. In contrast to previous studies, we have detected minute amounts of Ia (I-A) molecule on early B lineage (B220+IgM-) cells from normal bone marrow, using ELISA. The presence of the I-A molecule even on pro-B cells was deduced from experiments in which a monoclonal anti-I-A antibody completely blocked the generation of pre-B cells from B progenitor (B220-) cells in stromal cell-dependent B cell culture. Inasmuch as this antibody did not inhibit the maturation of pre-B cells to IgM+ B cells in culture, the I-A molecule on early B lineage cells probably plays a role in their maturation. We also examined the role of the I-A molecule in early B cell development, using transgenic mice harboring the antisense DNA to I-A beta-chain gene. The amount of I-A molecule on splenic B cells from the young transgenic mice decreased in the presence of abundant amounts of the antisense RNA. B cell development was perturbed in spleen from the transgenic mice. Stromal cell-dependent B cell cultures from these mice clearly showed that the maturation of B lineage cells was delayed at a very early stage of development (B220- to B220+). We propose that the I-A molecule on early B lineage cells may play an essential role in their maturation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal
  • Antigens, Surface / metabolism
  • B-Lymphocyte Subsets / cytology
  • B-Lymphocyte Subsets / immunology
  • B-Lymphocytes / cytology*
  • Bone Marrow Cells
  • Cell Differentiation
  • Cells, Cultured
  • Histocompatibility Antigens Class II / physiology*
  • In Vitro Techniques
  • Leukocyte Common Antigens
  • Mice
  • Mice, Transgenic
  • RNA, Antisense
  • Receptors, Antigen, B-Cell / metabolism


  • Antibodies, Monoclonal
  • Antigens, Surface
  • Histocompatibility Antigens Class II
  • RNA, Antisense
  • Receptors, Antigen, B-Cell
  • Leukocyte Common Antigens