title: The immunoregulatory role of bone marrow. IV. Role of an immunoenhancing glycoprotein derived from murine bone marrow.
abstract: Bone marrow-enhancing factor (B-EF) is the spontaneous product of whole bone marrow cells cultured in serum-free medium for a short term (24-48 hr). The factor is prepared by ultrafiltration of BMC supernates to yield a preparation with a MW of greater than 10,000. Production of the factor is not dependent upon antigenic or mitogenic stimulation of BMC, but is inhibited by treatment of BMC with cycloheximide. B-EF augments the in vitro primary PFC response to SRBC, as well as in vitro secondary IgM and IgG PFC responses to SRBC. Enhancement by B-EF is antigen dependent, genetically nonrestricted, and maximal when present at the initiation of culture. B-EF cannot induce a polyclonal antibody response like the polyclonal activator LPS. B-EF is directly mitogenic for thymocytes, bone marrow, and whole spleen cells, but fails to act as a costimulator of thymocyte proliferation in the presence of Con A. B-EF cannot support the growth of the IL-2-dependent cell line CTLL-2. Since B-EF has not been purified, the supernatant may contain more than one activity. The factor is heat labile at 65 degrees C and is sensitive to enzymatic digestion with trypsin and neuraminidase; this implies that B-EF may be a glycoprotein.
mesh_terms: D000276:Adjuvants, Immunologic / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D001853:Bone Marrow / Q000032:analysis / Q000276:immunology*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D006023:Glycoproteins / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D007376:Interleukin-2 / Q000502:physiology; D007700:Kinetics; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008811:Mice, Inbred DBA; D013045:Species Specificity; D000511:alpha-Macroglobulins / Q000502:physiology
chemical_list: D000276:Adjuvants, Immunologic; D006023:Glycoproteins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007376:Interleukin-2; D000511:alpha-Macroglobulins; C032306:polyclonal B cell activator