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Biomedical subjects

T L Rothstein

Publications and source records attributed to T L Rothstein.

At least 109 records · Page 6Linked to original sources

A rapid method for comparing monoclonal antibodies by limited proteolysis and electrophoresis.

A rapid and sensitive method for comparing the primary structure of proteins has been adapted to the study of monoclonal antibodies. Samples were digested with alpha-chymotrypsin in the presence of sodium dodecyl sulfate after which peptide fragments were separated into distinctive banding patterns by polyacrylamide gel electrophoresis. This method could easily detect differences in the primary structure of antibodies with related as well as unrelated binding specificities. In addition, antibody molecules derived by somatic diversification from the same germ line gene segments could be distinguished from one another.

Amino Acid Sequence↗

Proliferation of human malignant lymphocytes induced by anti-IgM independent of B cell growth factor.

Human malignant B lymphocytes were identified that proliferate in response to small doses of anti-immunoglobulin. Proliferation was induced by monoclonal mouse anti-HIgM, polyclonal goat anti-HIgM, and F(ab')2 fragments thereof, in vitro, and was not accompanied by immunoglobulin secretion. Proliferation was found to be unaffected by T cell depletion and was not enhanced by supplementation with B cell growth factor. Culture fluids from unstimulated malignant lymphocytes as well as from malignant lymphocytes stimulated with anti-HIgM contained no measurable B cell growth factor activity. Thus, proliferation of these malignant lymphocytes was not dependent on the presence of T lymphocytes and was independent of the presence of B cell growth factor. These results imply that B cell stimulatory factors may not be required for proliferation of all human B lymphocytes. Moreover, these results imply that treatment with anti-immunoglobulin reagents may be inappropriate for some B lymphocyte malignancies.

Antibodies, Anti-Idiotypic↗

Anti-immunoglobulin in combination with cytochalasin stimulates proliferation of murine B lymphocytes.

The ability of cytochalasin to influence the stimulation of murine B lymphocytes through surface immunoglobulin was assessed during short term cultures. Modest doses of anti-immunoglobulin alone did not stimulate proliferation of mouse spleen cells at 2 days. Cytochalasin B alone also had no effect. However, anti-immunoglobulin in combination with cytochalasin B stimulated substantial proliferation as judged by [3H]thymidine incorporation. Cytochalasins A, E, and D, and dihydrocytochalasin B were all effective in promoting B cell proliferation. Spleen cells from xid-defective (CBA/N X DBA/2)F1 male mice failed to proliferate in response to anti-immunoglobulin plus cytochalasin, suggesting that this treatment affects the same subset of B cells as anti-immunoglobulin plus B cell growth factor. Moreover, proliferation that was stimulated by anti-immunoglobulin plus cytochalasin B was not affected by T cell depletion. Cytochalasin may circumvent the need for, or replace, a second signal for proliferation.

Animals↗

Induction of idiotope suppression in the anti-azophenylarsonate response of T-depleted A/J mice.

The homologous, monoclonal antiidiotope, MB, induced idiotope suppression that was remarkably stable and could be transferred by B lymphocytes. Marked depletion of T cell function, confirmed by limiting diluting analysis, did not affect the ability of MB to suppress the corresponding idiotope. Suppression induced by MB appears to result from direct interaction with idiotope-positive B cells, without the intervention of idiotope-specific T suppressor cells.

Animals↗

Homologous monoclonal antibodies induce idiotope-specific suppression in neonates through maternal influence and in adults exposed during fetal and neonatal life.

The fine specificity of idiotype suppression induced early in ontogeny was investigated in the murine A/J anti-azophenylarsonate (Ar) response. Suppression was induced with two hapten-inhibitable, homologous monoclonal anti-idiotopic antibodies, AI and MB, that recognize partially overlapping sets of Ar-immune antibodies. Suppression was found to be idiotope-specific when adult mice were exposed to anti-idiotope as neonates; suppression was also idiotope specific when adult mice were exposed to anti-idiotope during fetal (through maternal inoculation) and neonatal life. Of particular interest, anti-idiotope, administered maternally, induced suppression in offspring first immunized with Ar as neonates, and this suppression was idiotope specific too. Thus, AI and MB induce idiotope-specific suppression in mice exposed to anti-idiotope early in ontogeny. These results parallel previous findings in adult mice and suggest that the mechanism of suppression in very young mice is the same as that in adults.

Aging↗

Fine specificity of idiotope suppression in the A/J anti-azophenylarsonate response.

Two hapten-inhibitable murine monoclonal antiidiotopic antibodies identified two idiotopes expressed by the heavy chain of hybridoma protein 36-65, whose amino acid sequence is encoded in the germ line of A/J mice. Among cross-reactive idiotype-positive hybridoma proteins and p-azophenylarsonate-immune antibodies, the two idiotopes were not always expressed together; some diversified antibodies expressed one idiotope without the other. Suppression that was induced by the two antiidiotopes was idiotope specific and corresponded to the fine specificities of these two reagents.

Animals↗

Computerized tomography as a diagnostic aid in acute hemorrhagic leukoencephalitis.

Computerized tomography (CT) in a pathologically proven case of acute hemorrhagic leukoencephalitis (AHL) showed a mass effect and increased absorption coefficient in the right hemisphere within 18 hours of the onset of neurological symptoms. The changes corresponded to the site of white matter edema, necrosis, and petechial hemorrhages demonstrated postmortem. The early changes of CT reflect the hyperacute nature of AHL and differ from those of herpes simplex encephalitis.

Acute Disease↗

Affinity analysis of idiotype-positive and idiotype-negative Ars-binding hybridoma proteins and Ars-immune sera.

The possibility that idiotype dominance may be associated with increased affinity for hapten was investigated in the murine A/J anti-p-azophenylarsonate (Ars) response. Fluorescence quenching of 14 Ars-binding hybridoma proteins by Ars-tyrosine was measured and Ka calculated using computer-assisted curve fitting. There was a 200-fold range in Ka for idiotype-positive hybridoma proteins, with 2 IgM hybridoma proteins being near the median. No clear difference in Ka was apparent between idiotype-positive (Id+) and idiotype-negative (Id-) hybridoma proteins. Ka was measured by fluorescence quenching on affinity-purified anti-Ars antibodies from 6 conventional antisera; there was no difference between Id+ and Id- (idiotype suppressed) sera. The affinities of the hybridoma proteins were correlated with the ratio of binding to Ars36-BSA and Ars10-BSA by direct radioimmunoassay. With this calibration, functional affinities of Ars-immune sera could be determined from relative binding ratios without the need for prior affinity purification. This was done for 18 Ars-immune sera, and again there was no clear difference between Id+ and Id- sera. Studies from this laboratory have identified the amino acid sequence of a hybridoma protein which corresponds to the germ line DNA sequence for the cross-reactive idiotype family. The present study shows that the protein directly encoded by the germ line gene has low affinity for hapten suggesting that somatic diversification operating on the germ line sequence can produce antibodies with increased affinity for hapten within the cross-reactive idiotype family. The present study also suggests that affinity is not the driving force behind idiotype dominance of the Ars-immune response.

Antibody Affinity↗

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. The evidence suggests the existence of a population of B lymphocytes that constitute a minor component of mIg+ cells having a high potential to make in vitro antibody responses. Users of techniques that utilize anti-Ig as a tool for separating B and T lymphocytes should carefully assess the extent to which residual B lymphocytes in the mIg- population contribute to antibody responses being studied.

Animals↗

Cranial neuropathy, myeloradiculopathy, and myositis: complications of Mycoplasma pneumoniae infection.

Polymyositis, transverse myelitis, ascending polyneuritis, bilateral optic neuritis, and hearing loss developed in a patient with high complement-fixing antibody titers to Mycoplasma pneumoniae. Each of her three children had primary atypical pneumonia with isolation of the organism. The neurologic disturbance is thought to represent a postinfectious complication of M pneumoniae infection.

Adult↗

Cytotoxic T lymphocyte sequential killing of immobilized allogeneic tumor target cells measured by time-lapse microcinematography.

Sequential killing of allogeneic target cells by immune cytotoxic T lymphocytes (CTL) was directly observed by time-lapse microcinematography. Target cells (EL4 lymphoma cells from C56BL/6 mice), coated with Fab fragments of goat antibody to EL4, were immobilized by binding to the floor of a polystyrene tissue culture flask that had been precoated with specifically purified anti-goat Fab. On adding immune BALB/c spleen CTL to such target cell monolayers it could be verified by direct observation that individual CTL could sequentially kill several target cells, that the CTL usually separated from the target cell before target cell death, that not all contacted target cells were killed, and that duration of contact was variable and not correlated with subsequent target cell death.

Animals↗

Mouse lymphocytes with and without surface immunoglobulin: preparative scale separation in polystyrene tissue culture dishes coated with specifically purified anti-immunoglobulin.

Mouse spleen cells could be preparatively separated into immunoglobulin positive (Ig+) and immunoglobulin-netative (Ig-)populations by incubating as many as 2 X 10(8) cells per 100 mm diameter petri plate coated with specifically purified goat anti-mouse immunoglobulin. The non-adherent population was 95% or more Ig-, and possessed graft versus host and cytotoxic effector activities, as would be expected for T cells. They could also give a mixed lymphocyte reaction and generate cytotoxic effector activity on culture in vitro. The adherent cells could not be released undamaged from plates coated with undiluted anti-Ig, but they could be released from plates coated with a 1/4 or 1/10 dilution of anti-Ig in an irrelevant antibody. The released cells were over 90% viable by trypan-blue staining, and 94% or more of the viable cells were Ig+.

Animals↗