Staphylococcal peptidoglycan: T-cell-dependent mitogen and relatively T-cell-independent polyclonal B-cell activator of human lymphocytes

Abstract

Staphylococcal cell wall products have been widely examined as probes for dissection of in vitro human immune responses. Mitogenic and polyclonal B-cellactivating properties have been attributed to intact cell walls or the protein A constituent thereof. We now report that staphylococcal peptidoglycan (PG), the major cell wall constituent, is not only a potent mitogen but also a polyclonal Bcell activator for human peripheral blood mononuclear cells (PBM). PG-induced proliferative responses of human PBM were comparable to that observed in pokeweed mitogen-stimulated cultures. As was true for pokeweed mitogen, PGinduced proliferation required the presence of T-cell help. Cultures of human PBM with PG also resulted in B-cell differentiation as reflected by an increase in numbers of immunoglobulin-secreting cells in stimulated cultures. In contrast to the proliferative response, PG-induced B-cell differentiation was relatively T-cell independent. This point became apparent when B-cell fractions were partially depleted of excessive numbers of monocytes before culture. Also, B-cell proliferation did not appear to be a major prerequisite for PG-induced B-cell differentiation responses. These data indicate that PG is a potent T-cell-dependent mitogen and relatively T-cell-independent polyclonal B-cell activator of human lymphocytes.

Increased serum IgG antibodies reactive with lipoteichoic acids in subjects with gingivitis

“…This is not to say, however, that LTAs cannot trigger harmful local effects. It is well-documented that LTAs activate the alternative pathway of the complement system; LTAs induced bone resorption in organ cultures (Hausmann 1974), and possessed powerful adjuvant properties and immuno-modulating ef-fects in in vitro studies (Miller, Urban & Jackson 1976, Levinson et al 1983). Recently, Lopatin & Kessler (1985) showed that antibody-dependent cellular cytotoxicity (ADCC) could be focused against cultured LTA-coated target cells.…”

Solubilized dental plaque is mitogenic for nylon wool‐purified human cord blood T lymphocytes

“…Antigens such as SLO stimulate maximal DNA synthesis after 5 to 6 d of culture, whereas mitogens such as PHA give maximal DNA synthesis after 3 d in culture. However, a 6-to 7-d peak in DNA synthesis is typical of human lymphocyte responses to known T celldependent B cell mitogens from bacteria such as LPS (Miller et al 1978), Staphylococcus aureus peptidoglycan (Levinson et al 1983), and PPD (Nilsson 1972), and is also typical of mitogenic T cell responses to alloantigens. Consequently, kinetic studies are not reliable criteria for distinguishing between antigenic and mitogenic responses.…”

“…The mitogenic polyclonal immunoglobuhn responses obtained with oral bacteria do not help with the interpretation of proliferative responses because the latter measure T cell as well as B cell proliferation (Mackler et al 1974, Stashenko et al 1983, Baker & Tondreau 1985a. Furthermore, B cell proliferation does not necessarily correlate with immunoglobulin production (Mangan & Lopatin 1981, Levinson et al 1983).…”

Staphylococcal LTA antagonizes the B cell-mitogenic potential of LPS

“…Bacterial antigens triggering T cell-independent immune responses can be classified into two types; type I antigens including LPS, peptidoglycans and lipoproteins have polyclonal B cell mitogenic activity 28 , 29 while type II antigens including most bacterial polysaccharides have no polyclonal B cell mitogenic activity, but do exhibit monoclonal B cell proliferative potential 30 . Our findings demonstrate that LTA alone has no mitogenic ability on B cells, and, thus, it can be excluded in the classification of type I Ti antigens.…”