Polyclonal activation of murine B lymphocytes by Fc fragments. I. The requirement for two signals in the generation of the polyclonal antibody response induced by Fc fragments
Morgan, E.L.; Weigle, W.O.
Journal of Immunology 124(3): 1330-1335
1980
ISSN/ISBN: 0022-1767 PMID: 6965691 Document Number: 159821
Fc fragments derived from human IgG1 induce murine splenic B lymphocytes to undergo proliferation and differentiation to antibody-secreting cells. The polyclonal antibody response was found to require both the presence of macrophages and T cells. Spleen cell cultures from nude mice or T cell-depleted normal mice proliferate to the level of untreated control mice but do not produce polyclonal antibody unless T cells are added. Regulation of the Fc fragment induced B cell differentiation to antibody synthesis apparently occurs through two distinct signals. One signal is provided by Fc fragments for proliferation and the other by T cells for differentiation. This suggestion is supported by the observation that spleen cell preparations, devoid of T cells, are capable of proliferation to the level of normal spleen cell cultures in response to Fc fragments, but are incapable of making a polyclonal antibody response. The cell population that responds to the differentiation signal also responds to the proliferative signal. "Hot pulse" experiments demonstrated that proliferation precedes polyclonal activation.