Search PubMed⌕ Search

Biomedical subjects

J Cerny

Publications and source records attributed to J Cerny.

At least 73 records · Page 4Linked to original sources
PubMed1986

Rapid changes in the regulatory potential of autologous anti-idiotopic T cells during an antigen-driven primary response.

The antibody response of C57BL/6 strain mice to Streptococcus pneumoniae R36a (Pn) is dominated by the T15 idiotype, but the responding cells appear to be idiotypically heterogeneous, in that individual antibody plaque-forming cells (PFC) may express some but not all idiotopes (Id) of the T15 complex. The presence of these distinct Id on the PFC was detected by a plaque-inhibition assay with three different monoclonal anti-Id antibodies, designated AB1-2, MaId5-4, and B36-82. A periodic change in the expression of AB1-2 and MaId5-4 Id was observed during primary (IgM) antibody response to Pn in the spleen. Those two Id were poorly expressed in the log phase of the response between day 2 and day 4 after immunization (few PFC in the spleen bore the Id), but they became detectable on the majority of PFC at the peak of the response, day 5 to day 7. The proportion of the Id-(AB1-2 or MaId5-4) positive PFC declined, again at day 10 after immunization. In contrast, the B36-82 Id was expressed on greater than or equal to 80% PFC throughout the entire primary response. The possibility that the apparent changes in the Pn-reactive cell populations are regulated by autologous anti-Id T cells was tested in vitro. Normal, unimmunized B cells were cultured with Pn, either alone or in the presence of syngeneic T cells isolated from the spleen of mice at the appropriate intervals after immunization: day 2 (T2), day 5 (T5), and days 10 to 14 (T10 to T14); T cells from unimmunized donors (T0) served as a control. The specific response after 4 days in culture was determined in regard to the total PFC as well as the proportion of PFC expressing the Id. Pn-stimulated B cells, alone or with the control T0 cells, produced moderate, variable levels of AB1-2+ and MaId5-4+ PFC. The expression of these two Id in the assay cultures was suppressed by addition of either T2 cells or T10-14 cells, but it was enhanced if T5 cells were added. However, these various T cell populations did not differ in their effect on the total PFC response. Also, the proportion of PFC bearing the third Id, B36-82 was high, and it was not consistently influenced by the added T cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

A novel idiotopic determinant on phosphorylcholine-binding immunoglobulins restricted to isotype and allotype.

A shared idiotopic (Id) determinant, designated B24-50, was detected on phosphorylcholine (PC)-binding myeloma proteins by using a monoclonal antibody. Analysis of immune sera from inbred and congenic strains of mice revealed the presence of this Id determinant on a very small proportion of the PC-binding immunoglobulins (Ig). Hybridoma and myeloma proteins of various classes were analyzed for B24-50 expression, and a clear association of B24-50 with IgA was demonstrated. The Id was found on two distinct idiotypic families, (TEPC15 and McPC603), which share a similar heavy chain but have different light chains; however, isolated heavy chains did not express B24-50. The Id did not require the absolute association of the TEPC15 light chain V kappa 22 with the TEPC15 heavy chain but appeared dependent upon the interaction of the light chain with the TEPC15 heavy chain via quaternary interactions and/or shared amino acid residues of V kappa 8 (M603) and V kappa 22. Furthermore, B24-50 was not found on IgA of strains with the Ighb allotype. Thus B24-50 is a novel isotype-restricted determinant found on two Id families and is influenced by the Igh allotype.

Animals↗
PubMed1985

Shared idiotypy between phosphorylcholine-specific antibody and acetylcholinesterase detectable by a monoclonal antibody.

Studies were undertaken to detect structural similarities between immunoglobulins and other proteins that bind to choline-containing ligands. Such proteins may share serologically detectable determinants that may not be predicted from the amino acid sequence alone. A monoclonal antibody was used that recognizes an idiotope near the phosphorylcholine binding site of the IgA myeloma TEPC15. This monoclonal anti-TEPC15 idiotopic antibody (anti-Id) also bound the enzyme acetylcholinesterase (AChE) as well as the nicotinic acetylcholine receptor from Torpedo californica. The anti-Id antibody also significantly decreased the AChE catalytic activity but did not affect the activity of an unrelated enzyme, horseradish peroxidase. These findings suggest that nonimmunoglobulin molecules share antigenic determinants with immunoglobulin that are associated with binding to structurally related ligands, and immune regulation may inadvertently affect the function of nonimmune systems.

Acetylcholinesterase↗
PubMed1985

Influence of genotype and the organ of origin on the subtype of T-cell in Moloney lymphomas induced by transfer of preleukemic cells from athymic and thymus-bearing mice.

Thymus, spleen, and bone marrow of 1-month-old neonatally Moloney murine leukemia virus-inoculated mice have been transferred to 400-R-irradiated syngeneic recipients of the opposite sex. The donor or recipient origin of T-cell lymphomas arising in the host animal was identified by the sex chromosome marker. Spleen and bone marrow of athymic BALB-nu/nu mice contain cells with the potential to develop into T-cell lymphomas upon transfer to thymus-bearing BALB/c recipients. Such lymphomas arise from at least two subsets of T-cells, one terminal deoxynucleotidyl transferase (TdT) positive and the other 20 alpha-hydroxysteroid dehydrogenase positive. The enzyme-negative precursor T-cells from the BALB-nu/nu spleen and bone marrow can thus mature to enzyme-positive cells and give rise to lymphoma in the thymus-bearing recipient. Preleukemic spleen and bone marrow, but not thymus, from CBA and BALB/c mice regularly contained cells with the potential to develop lymphoma. The subset of T-cell involved was influenced by the genotype since lymphomas arising after the transfer of CBA and BALB/c spleens were TdT positive and 20 alpha-hydroxysteroid dehydrogenase positive, respectively. In thymus-bearing mice, but not in nude mice, the transfer of preleukemic spleen cells gave lymphomas earlier than did transfer of bone marrow cells. This suggests that the more mature lymphoid cell population in the spleen of thymus-bearing mice may allow leukemic transformation to occur more rapidly than do the less mature cells in the bone marrow. In one-third of the cases, the virus produced by the preleukemic cells transferred induced new lymphomas involving recipient host cells. These de novo-induced lymphomas were all TdT positive. We suggest that leukemic transformation of TdT-positive cells may occur through a different mechanism than does transformation of cells bearing the 20 alpha-hydroxysteroid dehydrogenase marker.

20-Hydroxysteroid Dehydrogenases↗
PubMed1985

Regulation of idiotope expression. I. The effect of antigen dose on expression of certain T15 idiotopes during primary IgM response to S. pneumoniae R36a.

Clonal heterogeneity among B cells reactive to the same epitope may be determined through differences in idiotypy. It appears that clones bearing distinct idiotopes may constitute functionally distinct subpopulations. Data suggest that idiotopically distinct clones of PC-reactive B cells may be regulated independently of one another. We have looked to see whether individual T15+ clones may also differ in their requirements for activation. Here we examine the effect of immunizing doses of antigen on expression of two T15 idiotopes, B36-82 and B39-38, during both in vivo and in vitro primary responses to Streptococcus pneumoniae R36a (Pn) in CB-20 mouse strain. The idiotopes were detected on the specific antibody plaque-forming cells (PFC) by using monoclonal anti-idiotopic antibodies. We find that distinct patterns of idiotope expression are generated by stimulation with different doses of antigen. Immunization with suboptimal and super-optimal doses of Pn produced responses dominated by PFC expressing both idiotopes, whereas PFC induced by optimal antigen concentrations were primarily B36-82+ and B39-38-. These data indicate that the varying of antigen concentration may induce the response of different B cells bearing distinct idiotypes.

Animals↗
PubMed1984

Inhibition of plaque-forming cells with anti-idiotope or hapten: variation due to hapten density on indicator red cells.

Phosphorylcholine (PC)-specific antibody plaque-forming cells (PFC) were enumerated in the spleen of BALB/c mice immunized with S. pneumoniae R36a bacterial vaccine. Two indicator red blood cells were compared: RBC coupled with the hapten, PC-RBC, and cells coupled with PC-bearing polysaccharide from the pneumococcus, PnC-RBC. Equal numbers of direct (IgM) PFC were detected with both types of indicator cells. However, a significant difference appeared in the attempt to inhibit the respective PFC either with hapten (monovalent PC chloride, PCCl) or with monoclonal antibodies against T15 idiotopes (anti-Id). At optimal coupling concentrations, inhibition of anti-PnC-RBC plaques required a 10-fold higher concentration of the hapten when compared to anti-PC-SRBC plaques. Also, the inhibition of anti-PnC-SRBC plaques with anti-Id required much higher concentration of the antibody. The phenomenon may be explained by a higher epitope density on PnC-RBC than on PC-RBC. Heavily coupled PC-RBC were more difficult to inhibit (much like the PnC-RBC) by either the hapten or the anti-Id than lightly coupled PC-RBC. A mathematical analysis of the experimental curves supports the notion that under the assay conditions used, inhibition by either the hapten or the anti-Id is influenced primarily by antibody secretion rate and epitope density on indicator cells. If the 2 variables are too high, a significant inhibition of PFC with a low affinity anti-Id may not be possible. The theory also predicted that addition of a small amount of hapten into the assay would be roughly equivalent to secretion rate reduction and would facilitate the plaque inhibition by anti-Id. Indeed, we show a synergism between a minute (non-inhibitory) amount of PCCl and anti-Id in the inhibition of PC-specific PFC. These results point out that the detection of an idiotype-bearing PFC by plaque-inhibition assay is greatly influenced by technical variation in the assay, in particular, the preparation of the indicator red cells.

Animals↗
PubMed1984

Phenotypic heterogeneity of leukemias associated with Friend MuLV infection: studies on T-cell lymphomas and null cell leukemias in euthymic and thymus-deficient mice.

The development of leukemia/lymphoma in euthymic and congenitally thymus-deficient (nude) mice infected with Friend murine leukemia virus (Friend MuLV) was investigated; both groups developed fatal leukemias within 2-4 months post-infection but the gross and micropathology of lymphoid organs, coupled with cell-surface marker studies indicated the development of two distinct forms of disease. In euthymic mice one group developed lymphosarcomas manifested by thymoma, hepatosplenomegaly and lymphadenopathy whereas the second group developed splenic leukemias manifested only by hepatosplenomegaly. Analysis of surface markers on spleen cells from mice experiencing lymphosarcomas indicated that the majority of cells were positive for Thy 1.2, Moloney cell surface antigen (MCSA), and viral-coded gp70 and p30 antigens but negative for surface immunoglobulin (sIg). Euthymic mice experiencing splenic leukemias yielded spleen cells negative for Thy 1.2, sIg, and MCSA but positive for gp70 and p30. Nude mice uniformly developed splenic leukemias, spleen cells from which were Thy 1.2, MCSA, gp70 and p30 negative, although the proportion of sIg positive cells was higher than that observed in euthymic mice experiencing splenic leukemias. No correlation between the development of lymphosarcoma vs splenic leukemia and a pattern of ecotropic and/or xenotropic MuLV expression was observed. While ecotropic MuLV expression was equivalent in both euthymic and athymic mice, euthymic mice expressed approx. 10-fold higher levels of xenotropic MuLV than nude mice, however. Collectively the data suggest that infection of mice with Friend MuLV results in the development of two possible forms of disease, lymphosarcoma involving T cells vs splenic leukemia involving B and/or null cells.

Animals↗
PubMed1983

Activation of T cells in tumor-bearing mice.

Subcutaneous transplantation of the syngeneic P815 mastocytoma in DBA/2J mice induced an activation of splenic T cells which resulted in a hyperresponsiveness of the tumor-bearing animal to the unrelated antigens pneumococcal polysaccharide (Pn) and sheep red blood cells (SRBC). These tumor-activated T cells appeared to increase the plaque-forming cell (PFC) potential of suboptimal numbers of spleen cells, caused normal spleen cells to express increased numbers of PFC, and produced lymphokine(s) which also increased PFC responses of normal splenocytes. The tumor-activated T cells responsible for stimulating normal splenocytes in an in vitro antibody response were shown to be Ly+2- cells. The activity of the tumor-activated T-cell supernatants was not genetically restricted and required additional Ly1 T cells in order to induce rigorously clean B cells to produce antibody. The T cells capable of stimulating non-specific antibody responses were also capable of slowing tumor growth when injected with tumor cells in normal recipient mice. These results suggest that T cells activated by tumor antigens release immunostimulatory lymphokines and, at the same time, are capable of leading to inhibition of tumor growth.

Animals↗
PubMed1983

Augmentation of B-cell responsiveness by a tumor-activated T-cell factor.

The growth of the P815 mastocytoma in syngeneic DBA/2 mice led to an activation of Ly1+2- T cells. These T cells produced a soluble factor or factors in culture which, when added to normal spleen cells or B cells in the presence of syngeneic Ly1 cells, caused a genetically unrestricted augmentation of the plaque-forming response toward sheep red blood cells (SRBC). The culture supernatant of the activated T cells did not support the proliferation of an interleukin-2 (IL-2)-dependent cell, nor exhibit properties of late-acting TRF. Active supernatants appeared to affect directly B cells during the first 48 hr of culture with SRBC in such a way as to make them more responsive to antigen-specific Ly1-cell help.

Animals↗
PubMed1983

Induction of idiotype-specific suppressor T cells with antigen/antibody complexes.

The effects of immune complexes on the antibody response of BALB/c mice to Streptococcus pneumoniae R36a (Pn) were investigated. The cell wall polysaccharide (PnC) extracted from Pn was used to form complexes with TEPC-15, a myeloma protein that binds to phosphorylcholine determinants on the PnC. Complexes formed at equivalence were cultured with splenic T cells from BALB/c mice for 2 d, and then the cells were added to fresh BALB/c spleen cell cultures to test their effect on the antibody response to Pn, a response dominated by the T15 idiotype family. The results indicate that TEPC-15/PnC complexes induced potent suppressor T cells (Ts) whereas cells cultured with free antigen or free antibody alone had no effect on the plaque-forming cell response to Pn. The suppression was specific since the response to control antigens such as sheep erythrocytes was unaffected. The suppression appears to be idiotype-specific since the Ts had a relatively weak (and in some cases no) effect on the anti-Pn response of BALB/c mice that had been suppressed for T15 idiotopes by neonatal injection of a monoclonal anti-T15 antibody, MaId 5-4. Furthermore, cells cultured with TEPC-15/PnC complexes were shown to express specific receptors for TEPC-15 idiotopes. The results indicate that antigen/antibody complexes may have important immunoregulatory effects because they are potent inducers of idiotype-specific Ts.

Animals↗
PubMed1983

T and B lymphocyte susceptibility to murine leukemia virus moloney.

The susceptibility of T and B lymphocytes to productive infection and transformation by murine leukemia virus Moloney was determined by enumeration of cells producing infectious virus after in vitro infection of mitogen-stimulated, isolated cell populations and by in vivo infection of euthymic BALB/c and thymus-deficient (nude) mice. Our in vitro results demonstrated that the majority of splenic T cells and thymocytes are resistant to productive infection in vitro; a specific subpopulation of susceptible nylon-adherent splenic T cells was identified, however. Similarly, surface immunoglobulin-positive B cells also represent susceptible targets in vitro; mature B cells, however, did not represent the principal target for transformation in the in vivo experiments. Infected euthymic mice expressed increasing titers of murine leukemia virus and uniformly developed fatal T-cell lymphomas at 10 to 12 weeks postinfection; nude mice, in contrast, maintained high, stable levels of viremia throughout the 28 weeks of observation. Infected nude mice remained free of malignancy or developed either granulocytic leukemias or, in one case, reticulum cell sarcoma. Collectively, the results indicate that while the majority of T cells are resistant to productive infection, they represent the principle targets for transformation; B cells, however, represent permissive targets for virus replication, but are resistant to transformation.

Animals↗
PubMed1983

"Nonspecific" immunoenhancing T cells in tumor-bearing mice include anti-idiotypic subsets.

Splenocytes from DBA/2 mice inoculated 3 wk earlier with syngeneic P815 mastocytoma tumor cells produce increased numbers of antibody plaque-forming cells (PFC) when stimulated with either sheep red blood cells (SRBC) or phosphorylcholine (PC) on Streptococcus pneumoniae R36a in vitro. The nature of this nonspecific hyperreactivity was investigated in mixed cultures of purified splenic T and B cells. The addition of T cells from P815 tumor-bearing mice (TP815) into the cultures of normal B cells produced a significant enhancement of the PFC response to both SRBC and PC, when compared with the effect of normal T cells added to control cultures. The idiotypic profile of the enhanced anti-PC response was studied by a PFC-inhibition assay with monoclonal antibodies against two distinct idiotopic determinants (Id) of the T15 family. Normal B cells produced greater than 90% of T15 Id-positive (Id+) PFC. Addition of normal T cells diminished the proportion of T15 Id+ PFC to approximately 60%, whereas the rest of PFC were Id-. Addition of the immunoenhancing TP815 cells into the normal B cells cultures elevated the number of both T15 Id+ and Id- PFC responses, proportionally. However, when TP815 cells were first incubated on T15 protein-coated dishes and the non-adherent fraction was added to B cell cultures, the anti-PC PFC response remained enhanced but consisted of predominently T15 Id- PFC. These observations suggest that the early stage of P815 tumor growth activates various populations of specific helper/amplifier T cells including subsets with anti-idiotypic activity and that the generalized increase of antibody response to various antigens in tumor-bearing mice may be regarded as a polyclonal activation of specific T cells.

Animals↗
PubMed1982

Immunoglobulin idiotopes expressed by T cells. I. Expression of distinct idiotopes detected by monoclonal antibodies on antigen-specific suppressor T cells.

The idiotopic repertoire expressed by antigen-specific suppressor T cells (Ts) generated by Streptococcus pneumoniae strain R36a (Pn) in BALB/c strain mice was investigated using a panel of five monoclonal anti-idiotopic antibodies against TEPC-15/HOPC-8 myeloma proteins. Previous studies suggested that the anti-idiotopic antibodies recognize distinct idiotopic determinants within the T15 idiotype, and that Pn-reactive B cells express all of those idiotopes as shown by a specific inhibitory effect of the anti-idiotopic antibodies on induction of anti-Pn response in vitro as well as on the mature antibody plaque-forming cells. In this study we asked the question of whether anti-idiotopic (Id) can block the inductive and/or effector phases of generation of Ts which act on the Pn-reactive B cells. The presence of anti-Id during the activation of T cells with Pn did not prevent the generation of Ts. However, suppression mediated by Ts on responder lymphocytes (cultures of spleen cells or B cels) was inhibited (reversed) by four out of five anti-Id. Some of the antibodies recognize hapten (phosphorylcholine)-inhibitable Id in the paratope of Ig whereas others are directed against nonparatopic Id. These data indicate that the antigen receptor on Ts includes VH sequences both within and without the immunoglobulin in paratope, and that the Id repertoir of Ts overlaps with that of B cells.

Animals↗