PubMed Health⌕ Search

Biomedical subjects

M B Rittenberg

Publications and source records attributed to M B Rittenberg.

At least 73 records · Page 4Linked to original sources
PubMed1980

IgG B memory cell subpopulations: differences in susceptibility to stimulation by TI-1 and TI-2 antigens.

Spleen cells from mice primed with the thymus dependent (TD) antigen trinitrophenyl keyhole limpet hemocyanin several months earlier can be stimulated in vitro to produce an IgG anti-hapten response to TD as well as thymus independent (TI) forms of the hapten. Selective killing of TD or TI-2 responding B cells can be accomplished with the corresponding antigen by bromouridine deoxyribose (BUdR) and light treatment without affecting the other population. In contrast, we show here that selective killing with TI-1 antigens does not occur. Rather, the TI-1 antigens, TNP-Brucella abortus or TNP-lipopolysaccharide, eliminate both TD and TI-2 responding IgG memory B cells. All TNP-responding B cells are similarly eliminated if cultures are challenged simultaneously with TD and TI-2 antigens before BUdR and light but not when they are challenged with either a TD or TI-2 antigen separately. We conclude that IgG memory B cell precursors stimulated to produce anti-TNP by TD or TI-2 forms of the hapten are defined by only two functionally distinct subpopulations and that TI-1 antigens can stimulate both of these populations at least to divide.

Animals↗
PubMed1979

Cross-reactivity of rat, mouse, and human IgD.

Highly purified sheep anti-rat lymphocyte membrane IgD (mIgD) was used to detect cross-reactivity with the putative murine-delta chain on mouse lymphocytes. Cross-reactivity is demonstrated by indirect immunofluorescent staining and by immunoprecipitation of 125I-labeled lymphocyte membrane extracts followed by electrophoresis on 10% polyacrylamide gels. In addition, cross-reactivity of anti-rat-delta with human IgD is shown by gel diffusion analysis. The anti-rat-delta reagent stained both Ig5a+ and Ig5b+ lymphocytes. Preincubation of Ig5b+ (but not Ig5a+) cells with monoclonal allotype-specific antibodies (anti-Ig5b) under capping conditions caused inhibition of staining by the sheep anti-rat-delta reagent, indicating that it is the delta-chain that is recognized on mouse lymphocytes and that the anti-rat-delta reagents does not distinguish between mouse-delta allotypes. Furthermore, absorption of the sheep anti-rat-delta serum with purified human IgD reduced subsequent staining of mouse lymphocytes by approximately 50%; staining was not affected by absorption with human IgM. This xenogeneic anti-delta antiserum appears to detect determinants on the delta-heavy chain, which are shared by at least three species of mammals, suggesting that these determinants represent important molecular features conserved during evolution.

Animals↗
PubMed1979

Hemolytic anemia due to pyruvate kinase deficiency: characterization of the enzymatic activity from eight patients.

We have studied the red cell pyruvate kinase (PK) variants from eight patients representing five families with pyruvate kinase deficiency-associated hemolytic anemia. The kinetic properties, electrophoretic mobilities, and immunological reactivity with anti-normal red cell pyruvate kinase were determined. The patients differ in the severity of their clinical condition and in the molecular properties of their red cell pyruvate kinase variants. The most seriously affected patient (PK Beaverton) has no electrophoretically demonstrable red cell isozymes. The activity present is due to the M2 isozyme, however red cell isozyme can be detected immunologically. PK Molalla and PK Lake Oswego are thermolabile variants with normal kinetic parameters. PK Molalla, in addition, has altered electrophoretic mobility. PK Multnomah and PK Milwaukie have decreased affinity for the substrate phosphoenolpyruvate, and PK Multnomah also has altered electrophoretic mobility. PK Coos Bay shows electrophoretic variation and a slightly decreased affinity for phosphoenolpyruvate consistent with an increased modulating effect of fructose-1,6-diphosphate.

Adolescent↗
PubMed1978

Independent precursors for thymus dependent and thymus independent IgG memory B cells.

Spleen cells from mice primed with the thymus dependent antigen trinitrophenyl keyhole limpet hemocyanin several months earlier can be cultured in vitro to give vigorous IgG antihapten PFC responses to thymus dependent and thymus independent forms of the hapten. The IgG memory precursors responding to these two forms of the hapten constitute functionally distinct subpopulations which we have designated as B1gamma and B2gamma to represent the precursor cells responding to the thymus independent and thymus dependent antigens respectively. Four types of evidence for these subpopulations are presented 1) the responses to the two types of antigen are additive when both forms are added to the same culture; 2) the precursor frequency for the thymus dependent and thymus independent populations is different although expansion over primary IgM precursor frequencies was not detectable; 3) the avidities of the PFC elicited by each antigen are distinct; the thymus independnet antigens elicit lower avidity PFC; 4) selective killing of one population can be accomplished by BUdR and light treatment without affecting the other population.

Animals↗
PubMed1978

Distinct subpopulations of IgG memory B cells respond to different molecular forms of the same hapten.

Spleen cells from mice primed with the thymus-dependent antigen trinitrophenyl keyhold limpet hemocyanin several months earlier can be cultured in vitro to give vigorous IgG antihapten PFC responses to thymus-dependent (TD) and thymus-independent (TI) forms of the same hapten. Here we show that the IgG memory precursors that respond to these two forms of the hapten constitute functionally distinct subpopulations. We have designated these subpopulations as B1gamma and B2gamma to represent secondary precursor cells responding to TI and TD antigens, respectively. Three types of evidence for these subpopulations are presented: 1) In vitro secondary IgG responses to TD and TI forms of the TNP hapten are additive when both forms are added to the same culture. 2) The precursor frequencies for the TD and TI antigens are additive, but addition is not observed between two TD or two TI antigens. 3) Each population can be selectively eliminated by BUdR and light treatment without affecting the other population. The ontogenetic relationships between these subpopulations are discussed in relation to all presently proposed subpopulations B1mu, B2mu, B1gamma, and B2gamma.

Animals↗
PubMed1977

Down regulation in B lymphocytes: low dose signals.

Picogram quantities of dinitrophenylated (DNP) dextran, a thymus-independent antigen or lipopolysaccharide, a B cell mitogen, signal down B lymphocytes to unresponsiveness. Down signals were detected by a decision test in which signaled lymphocytes were allowed one hour to react to an immunogenic pulse of DNP-dextran. Depletion of T cells or macrophages did not interfere with the generation of down signals. The signaling can proceed entirely at 4 degrees C and it its negative effect is transitory. Down signals which could be detected after 15 min at 37 degrees C were reversed by 60 min. It is suggested that down regulation by low dose antigenic signals provides a means of distinguishing background noise from true antigenic stimuli.

Animals↗
PubMed1977

Purification and characterization of human muscle pyruvate kinase.

The M1 isozyme of pyruvate kinase has been purified from human psoas muscle in a seven-step procedure. Fractionation by ammonium sulfate precipitation, heat treatment, acetone precipitation, diethylaminoethyl cellulose batchwise treatment followed by chromatography on carboxymethyl cellulose and Sephadex G-200 gave a product with a specific activity of 383 U/mg representing a 294-fold purification with a yield of 11%. The product formed orthorhombic crystals and was homogeneous on polyacrylamide gel electrophoresis with and without sodium dodecyl sulfate, sedimentation velocity, sedimentation equilibrium, and immunodiffusion. The purified enzyme has a molecular weight of 240700 and has a sedimentation coefficient (S20,W) of 10.04S. It contains four subunits with identical molecular weights of 61000. No free N-terminal amino acids could be detected. Antibody prepared against the purified human M1 isozyme does not cross-react by immunodiffusion or enzyme inactivation with the human erythrocyte isozyme and in the reverse experiment antibody prepared against human erythrocyte pyruvate kinase does not cross-react with the purified M1 isozyme. The amino acid composition of the M1 isozyme is presented.

Amino Acids↗
PubMed1976

Antigenic relationships on the diphtheria toxin molecule: antitoxin versus antitoxoid.

We used the mouse to produce antisera to native diphtheria toxin and diphtheria toxoid. With these antisera it was possible to distinguish between toxin and toxoid. By gel diffusion analysis, antitoxin detected antigenic determinants on toxin which were not available on toxoid, indicating that some determinants had been lost or altered by formalin treatment. Antitoxoid, on the other hand, showed reactions of identity between toxin and toxoid in gel diffusion. The toxin neutralization titers measured in tissue culture were the same for both antisera. Only antitoxin neutralized the adenosine 5'-diphosphate ribosyl-transferase activity of fragment A, but suprisingly both antisera had significant anti-fragment A titers when tested by passive hemagglutination. It is suggested that some of the anti-fragment A activity in antitoxin affects the enzyme active site, whereas that in antitoxoid does not, implying the existence of a least two independent antigenic regions on fragment A.

Animals↗
PubMed1976

Evidence for separate subpopulations of B cells responding to T-independent and T-dependent immunogens.

BALB/c spleen cell cultures were double-challenged with optimal doses of TNP-T independent and TNP-T-dependent immunogens. The anti-hapten response was additive or synergistic in double challenged cultures compared to the response in cultures challenged with either immunogen alone. A high, suppressive dose of either immunogen did not prevent the response to an optimal dose of the second immunogen in the same culture. Spleen cell cultures were also double challenged with combinations of two T-dependent or two T-independent immunogens. Addition or synergy in the anti-hapten response only occurred when the double challenge consisted of a mixutre of T-dependent and T-independent immunogens. These results are consistent with the proposed B1B2 classification of B cell subpopulations.

Animals↗