Rhinosporidiosis in a dog.

Rhinosporidiosis was diagnosed in a black and tan coonhound. Clinical signs were characterized by 6 to 8 months of intermittent sneezing. Numerous polypoid nodules were removed from the nasal cavity.

Interaction of helper T cells and Lyb5+ B cells responding to phosphorylcholine is MHC-restricted.

The requirements for T cell/B cell interaction for the induction of primary in vitro antibody responses to phosphorylcholine (PC)-keyhole limpet hemocyanin (KLH) were examined. Long-term helper T cell lines derived from KLH-primed (CBA/N X BALB/c) F1 female mice (H-2k/d) were able to support a T15-idiotype dominant, IgM anti-PC response of BALB/c (H-2d) B cells and macrophages, but could not activate PC-specific responses by BALB.B (H-2b) B cells, even in the presence of irradiated H-2k/d antigen-presenting cells.

Negative selection in vivo reveals expression of strong Mls determinants in mice with X-linked immunodeficiency.

Evidence is presented that mice with X-linked immunodeficiency (xid) express strong Mlsa,d determinants, a putative marker of the mature subset of B cells. Although young (3-5 wk) (CBA/N X DBA/2)F1 male (xid+) mice stimulated only very weak mixed lymphocyte reactions (MLR) to Mlsa,d determinants, older mice (greater than 7 wk) regularly elicited conspicuous responses, despite being totally unresponsive to TNP-Ficoll. Expression of Mlsa,d determinants by xid+ mice was also detected by the procedure of negative selection in vivo.

Activation of B lymphocytes by monovalent anti-Lyb-2 antibodies.

Although activation of B lymphocytes by antigen or anti-Ig antibody has been shown to require cross-linking of surface Ig molecules, cross-linking is not necessary for B cell activation by anti-Lyb-2 monoclonal antibody (MAb). Monovalent Fab' fragments of anti-Lyb-2 MAb are as effective as the intact antibody in inducing blast cell transformation of small B cells and B cell proliferation in the apparent absence of T cells and adherent cells. In the presence of factors from T cells, B cells activated by Fab' fragments of anti-Lyb-2 MAb were induced to mature into Ig-secreting cells.

Induction of B lymphocyte proliferation by monoclonal anti-Lyb 2 antibody.

Monoclonal antibody to Lyb 2, a differentiation antigen present on all B cells, has been used to study the role of Lyb 2 molecules in B cell activation. Monoclonal anti-Lyb 2 antibody (m-anti-Lyb 2) transforms resting B cells into blast cells and induces proliferation in these activated B cells. The proliferative response to anti-Lyb 2 is a property of the Lyb 5+ subset of B cells, since the antibody fails to stimulate B cells from mice expressing the CBA/N immune defect.

Lyb-8.2: A new B cell antigen defined and characterized with a monoclonal antibody.

A DBA/1 B10.D2-specific monoclonal antibody (CY34) is described which defines a new murine B lymphocyte differentiation antigen designated Lyb-8.2.

Lyb antigens and their role in B lymphocyte activation.

Anti-Lyb 7 antibodies selectively inhibit in vitro immune responses to the TI-2 antigens but not to TI-1 antigens. The Lyb 7 differentiation antigen is distinct from Lyb 5 and is coded by genes linked to IgCH loci. Lyb 8 is a new B cell differentiation antigen defined by a monoclonal antibody.

Primary in vitro antibody responses by purified murine B lymphocytes in serum-free defined medium.

A serum-free medium formulation that allows a primary in vitro antibody response to the nonmitogenic thymic independent antigen TNP-AECM-Ficoll is described. Purified murine B lymphocytes and adherent accessory cells are required for optimal specific responses as well as for optimal B cell survival. The medium is based on Iscove's modification of Dulbecco's modified Eagle's medium and Ham's F-12 nutrient mixture.

Antigen-specific helper T cells required for dominant idiotype expression are not H-2 restricted.

Two synergizing antigen-specific helper T (Th) cell populations are required for an optimal TEPC15 (T15)-dominated antiphosphorylcholine (PC) plaque- forming cell response . In these studies, the two Th cell sets are shown to differ in their requirements for recognition of self-major histocompatibility complex (MHC)-encoded determinants by testing the ability of Th cells from F(1) {arrow} parent bone marrow chimeras to collaborate with PC-specific B cells bearing MHC-encoded determinants of either parental haplotypes. Previous studies have shown that one antigen-specific Th cell population is required for T-dependent anti-PC responses and activates PC-specific B cells only if the hapten, PC, is physically linked to the priming antigen.

All-female fish: a cryptic species of menidia (atherinidae).

Electrophoretic evidence revealed the common occurrence of an all-female species of Menidia (Pisces: Atherinidae) at two localities separated by 280 kilometers on the Gulf Coast of Texas. This finding adds significantly to the known taxonomic spectrum of unisexuality in fishes and demonstrates that unisexuality may be more common among fishes that do not bear live young than is generally suspected.

High anti-TNP plaque-forming cell potential of residual mIg+ cells in a T cell population.

In the course of experiments designed to study the immune response of purified populations of B lymphocytes to thymus-independent (TI) antigens, a variety of cell purification procedures were followed. In using anti-immunoglobulin-coated dishes to separate lymphocytes bearing membrane immunoglobulin (mIg) from mIg- lymphocytes, it was found that the nonadherent fraction, which was predominantly mIg-, complement receptor negative, and nonresponsive to the B cell mitogen lipopolysaccharide, gave very substantial anti-TNP plaque-forming cell responses to 2 TI antigens. These responses could be inhibited by incubation of such cells in the presence of anti-mu and thus appeared to be attributable to mIg+ cells.

Cellular requirements for antigen presentation in the induction of a thymus-independent antibody response in vitro.

The ability of various cell populations to bind and present the thymus-independent antigen TNP-Ficoll to a responding cell population was assessed. The in vitro antibody response to TNP-Ficoll depends upon the presence of B lymphocytes and plastic-adherent accessory cells, but does not require T lymphocytes. Purified B cells were the most effective population in binding and presenting TNP-Ficoll, and adherent cells did not perform this function.

Cell cooperation during in vivo anti-hapten antibody responses. VI. Evidence for an allogeneic effect replacing one of two helper T cells.

T and B lymphocyte activity in adoptive secondary antibody responses was assessed by cell titration in mice of the X-linked immune defective CBA/N strain and mice of their normal partner strain CBA/CaJ. No quantitative differences could be detected in either T or B cell activity in these experiments, in which 2,4-dinitrophenyl was used as the hapten. Both of the helper T cells detected in such assays were present in both strains.

Mice whose B cells cannot produce the T15 idiotype also lack an antigen-specific helper T cell required for T15 expression.

The X-linked CBA/N defect in B cell function precludes an antibody response to phosphorylcholine (PC). Accordingly, (CBA/N X BALB/c)F1 male mice are unresponsive to PC and lack circulating immunoglobulin bearing the T15 idiotype characteristic of BALB/C anti-PC antibody. In contrast, (CBA/N X BALB/c)F1 female mice respond to PC and greater than 80% of the anti-PC antibody is T15+.

Lyb-7, a new B cell alloantigen controlled by genes linked to the IgCH locus.

Anti-Lyb-5.1 serum contains antibodies against two different B cell surface antigenic determinants, Lyb-5.1 and Lyb-7.

Role of a nonimmunoglobulin cell surface determinant in the activation of B lymphocytes by thymus-independent antigens.

Lyb 5 is a B-cell alloantigen which is expressed on 50-60% of B cells. It was defined originally on the basis of cytotoxicity. We have described a new reactivity within the anti-Lyb 5 serum on the basis of selective inhibition of antibody responses in vitro by this antiserum in the absence of complement.

Ontogeny of susceptibility of mouse splenic B cells to tolerance induction in vitro by TNP-D-GL.

The susceptibility of mouse spleen cells to hapten-specific tolerance induction of a primary in vitro thymus-independent antibody response was examined. Both the induction of tolerance by 2,4,6-trinitrophenyl-D-glutamic acid-D-lysine (TNP96D-GL) and of antibody formation (elicited by TNP-Brucella abortus) in neonatal spleen cell cultures were unaffected by anti-Thy-1.2 plus complement treatment.

Activation of mouse lymphocytes by anti-immunoglobulin. II. A thymus-independent response by a mature subset of B lymphocytes.

Mouse spleen cells can be stimulated to proliferate in vitro by purified anti-mu or anti-gamma,kappa antibodies. These responses can be obtained in cell populations bearing membrane immunoglobulin (Ig), purified by the fluorescence activated cell sorter (FACS), but they are not observed in FACS-purified Ig- cell populations. Furthermore, treatment of spleen cell populations with anti-Thy 1.

Anti-idiotype induced regulation of helper cell function for the response to phosphorylcholine in adult BALB/c mice.

An adoptive secondary antibody response to phosphorylcholine (PC) can be generated by the transfer of keyhole limpet hemocyanin (KLH)-primed T cells, PC-bovine gamma globulin-primed B cells, and PC-KLH into irradiated syngeneic BALB/c mice. If the KLH-primed T-cell donors were pretreated with anti-idiotype antibodies directed against the BALB/c PC-binding myeloma TEPC 15, their T cells were unable to collaborate effectively with PC-primed B cells; moreover, they could suppress the helper activity of T cells from normal mice for the PC-KLH response. The Ly phenotype of these T cells was found to be Ly 1-, 2+.

Induction of B cell priming by neonatal injection of mice with thymic-independent (type 2) antigens.

Mice injected at birth with the thymus-independent type 2 antigen TNP-AECM-Ficoll have augmented anti-TNP antibody responses when their spleen cells subsequently are challenged in vitro with TNP-coupled thymic independent or thymic dependent antigens. This neonatal priming effect was shown to occur in neonatal nu/nu mice and thus does not appear to require T lymphocytes. The primary explanation for the priming effect seems to be an increase of approximately 10-fold in the numbers of TNP-specific precursors of antibody-forming cells.

T-independent responses in B cell-defective CBA/N mice to Brucella abortus and to trinitrophenyl (TNP) conjugates of Brucella abortus.

CBA/N mice have an X-linked immune defect in B lymphocyte function which leads to their inability to respond to several thymus-independent antigens. We report here that these mice and immunologically defective F1 male (CBA/N X DBA/2N) mice can respond to Brucella abortus and to 2,4,6-trinitrophenyl derivatives of Brucella abortus (TNP-BA). These responses can be obtained in vivo and in vitro and are thymus-independent by the criteria that (a) they can be transferred to irradiated recipients by bone marrow cells and anti-Thy-1.