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M P Cancro

Publications and source records attributed to M P Cancro.

34 records · Page 2Linked to original sources
PubMed1988

Patterns of Ig V region expression among neonatal hemagglutinin-responsive B cells. Evidence for non-random VH gene representation during later stages of development.

Hybridoma libraries were established whose specificities reflect those within the BALB/c hemagglutinin-responsive B cell repertoire at 1 or 2 wk of age. These libraries were generated through chronic immunization regimes that induce responses dominated by clonotypes available at the age of initial immunization. Dot blot analyses of cytoplasmic RNA from these hybridomas were performed to determine the Ig H chain V region (VH) families associated with the repertoire at each age. Although genes from most known VH families can generate hemagglutinin-specific antibodies, clonotypes prevalent during the first week of life disproportionately use VH7183 gene segments. In contrast, hybridomas representative of the repertoire in 2-wk-old individuals preferentially use VHS107, VH36-60, and VHX24 gene segments. These results demonstrate changes in VH gene family predominance that correlate with the age-related patterns of clonal emergence and turnover previously shown in the hemagglutinin-reactive B cell pool. Taken together, these findings suggest that the very early neonatal Ag-responsive B cell pool closely reflects preferential VH gene rearrangements within the pre-B cell compartment. Further, they suggest that either non-random strategies of VH gene expression, or selective clonal expansion strategies based on VH, operate even at later stages of development.

Aging↗
PubMed1988

Characterization of an inbred mouse exhibiting low responsiveness to phosphorylcholine. Antibodies from low-responder mice suggest gene conversion events within the S107VH gene family.

An inbred strain was derived from feral mice that respond poorly to phosphorylcholine (PC) but responded normally to a variety of other Ag. Low responsiveness is inherited as a single recessive autosomal trait, characterized by very low levels of both PC-binding serum antibody and PC-specific B cells. Analyses of PC-reactive clonotypes generated in limiting dilution culture, as well as analyses of PC-specific hybridomas, indicate that this strain expresses L and H chain V regions not previously associated with high affinity murine PC-binding antibodies. Further, sequence analyses suggest gene conversion events occurred within the S107VH gene family among the progenitors of this strain subsequent to their divergence from those of most common laboratory strains.

Amino Acid Sequence↗
PubMed1985

Cellular basis for neonatally induced T-suppressor activity. Primary B cell maturation is blocked by suppressor-helper interactions restricted by loci on chromosome 12.

The cellular mechanism and genetic restriction of neonatally induced HA-specific suppressor T (Ts) cells have been examined. The in vivo effect of these Ts cells on antibody production, primary B cell proliferation, B cell surface marker changes, and helper T (Th) cell priming during primary responses to HA have been determined. The results indicate that, although antigen-induced B cell proliferative responses and surface marker changes occur in the presence of Ts cells, differentiation to Ig secretion, and long-lived memory B cell production are prevented. Further, antigen-specific Th cell priming is completely ablated by Ts cells, suggesting that Ts act by preventing the delivery of Th signals required for both the later stages of primary B cell maturation, and the formation of memory B cell populations. Finally, in vivo cell mixing experiments using congenic mice indicate that this Ts-Th interaction is restricted by loci on mouse chromosome 12.

Animals↗
PubMed1983

Restricted adult clonal profiles induced by neonatal immunization. Influence of suppressor T cells.

The effects of neonatal antigen exposure on the adult B cell repertoire have been examined by characterizing the influenza hemagglutinin (HA)-specific response of adult BALB/c mice given antigen soon after birth. Ligand exposure during early life exerts a profound and lasting effect upon the B cell repertoire, characterized by the expansion and preservation of particular antigen-reactive clones and the apparent loss of others. The precise subset of clonotypes selectively preserved depends upon the age at which antigen is first encountered; and is predictable given a knowledge of the emerging primary pool's dynamics and composition. The preserved (secondary) B cells differ from their unprimed precursors with respect to (a) expression of the surface marker detected by the monoclonal antibody J11d, and (b) susceptibility to T cell-mediated suppression. These studies thus demonstrate a strong relationship between the heritable dynamics of the emerging primary B cell repertoire and the effect of ligand-driven events upon repertoire phenotype. In addition, they provide a mechanistic model for certain forms of antigen-induced oligoclonal dominance, especially the phenomenon of original antigenic sin.

Aging↗
PubMed1982

Multiple loci mediate B cell repertoire ontogeny: analysis of the hemagglutinin-specific repertoires in neonatal C.B20 and (C.B20 x B10.D2)F1 mice.

The HA-specific B cell repertoires of 12 to 14-day-old C.B20 and (C.B20 X B10.D2)F1 mice have been characterized and compared to those of BALB/c, B10.D2, and (BALB/c X B10.D2)F1 mice to assess the role of allotype-linked loci in the process of repertoire formation. Both C.B20 and (C.B20 X B10.D2)F1 neonates express repertoires similar to (BALB/c X B10.D2)F1s of the same age, and allotypic analysis indicates that nonparental clonotypes observed in (BALB/c X B10.D2)F1s at this developmental stage are derived predominantly from the B10.D2 parent. In conjunction, these findings indicate that: a) allotype-linked loci, although influential in repertoire formation, clearly interact with loci elsewhere in the genome to shape the expressed repertoire phenotype; b) developmental preference may exist among heterozygous individuals regarding the time at which particular elements of each parental VH haplotype are expressed; and c) the factors that control this preference are dictated by heritable elements unlinked to Ig allotype loci.

Animals↗
PubMed1982

Dynamics of B cell repertoire formation: normal patterns of clonal turnover are altered by ligand interaction.

The dynamics of B cell repertoire formation was examined by defining the kinetics and clonal composition of the influenza hemagglutinin- (HA) responsive BALB/c repertoire at 1 and 2 wk of age. Although the size and diversity of the HA-responsive repertoire remain constant during this period, the clonal composition changes significantly. These findings indicate a rapid and regular turnover of clonal specificities within the emerging primary repertoire. In addition, the effect of ligand exposure on this process was analyzed by characterizing the repertoire of 2-wk-old BALB/c mice that had been immunized with virus during their first week of life. This treatment markedly alters the normal kinetics and turnover of the emerging repertoire. First, many clonotypes that normally arise between 1 and 2 wk of age fail to be expressed in detectable numbers. Second, several clonotypes that are normally only transiently expressed at 1 wk of age are preferentially expanded and preserved within the responsive B cell pool. In conjunction, these results demonstrate that a) the primary repertoire is characterized by rapid and regular turnover in clonotype composition, b) antigenic exposure perturbs the normal kinetics and pattern of this turnover, and c) the exact effects of ligand exposure may depend on the developmental stage at which it occurs.

Age Factors↗
PubMed1981

Detection of enzyme polymorphism by using monoclonal antibodies.

Six monoclonal antibodies against human placental alkaline phosphate [orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1], a highly polymorphic enzyme, were tested for reactivity against a panel of 295 placental extracts that had been typed electrophoretically. The products of the three common alleles as well as several rare alleles could be discriminated by the various antibodies. In some cases differences between allelic products were reflected by essentially "all-or-none" reactions, but in other cases the differences were smaller and demonstrable only by quantitative analysis of the binding. Evidence for allelic differences not detectable electrophoretically was also obtained.

Alkaline Phosphatase↗
PubMed1981

B cell repertoire ontogeny: heritable but dissimilar development of parental and F1 repertoires.

This study examines the genetics of antibody repertoire ontogeny by the comparison of the repertoires in B10.D2, BALB/c, and (BALB X B10.D2)F1 mice at 12 to 14 days of age. This was accomplished by fine specificity analysis of clonotypes responsive to the influenza virus hemagglutinin in each strain. The results indicate that: a) neonatal antibody repertoires are in general less heterogeneous than their adult counterparts, which confirms and extends previous observations and reinforces the assertion that repertoire ontogeny is a heritable, patterned process; b) the BALB/c and B10.D2 neonatal repertoires differ from one another in clonotype compositions, facilitating genetic analyses of repertoire establishment; c) the BALB/c X B10.D2)F1 neonatal repertoire, although of restricted heterogeneity, is clearly dissimilar from either parental repertoire. These findings indicate that B cell repertoire ontogeny may be governed by heritable factors that interact with but are not necessarily themselves variable region structural genes. Furthermore, it appears that the expressed responsive B cell repertoire is a selected subset of the inherited potential repertoire.

Animals↗
PubMed1980

B cell repertoire diversity in athymic mice.

The extent of B cell repertoire diversity among nu/nu BALB/c mice has been assessed and compared with that of normal BALB/c mice. This was accomplished through the characterization of monoclonal, influenza hemagglutinin-specific antibodies by reactivity pattern analysis. The results indicate that the repertoire of athymic mice is equivalent in diversity to that of normal mice. Moreover, because these responses were obtained in recipients that were histocompatible but distinct at immunoglobulin allotype loci, these findings indicate that a very diverse array of B cell clonotypes may be stimulated in the absence of allotype-identical T cells.

Animals↗
PubMed1979

Patterned acquisition of the antibody repertoire: diversity of the hemagglutinin-specific B-cell repertoire in neonatal BALB/c mice.

The B-cell response of 12- to 14-day old BALB/c mice to the hemagglutinin molecule of influenzae virus A/PR/8/34(H0N1) has been examined with monoclonal antibodies obtained by the splenic focus technique. An analysis of the specificity of these antibodies with a panel of heterologous viruses indicates that the antibody repertoire is highly restricted at an intermediate stage in postnatal development of the immune system. In toto, only 10 distinct reactivity patterns have been observed in an analysis of 72 antibodies derived from 28 donors. This contrasts with a substantially more diverse repertoire present in nonimmune and immune adult populations. The neonatal antibody specificities do not appear to be a random sampling of adult specificities, because several clonotypes (as defined by reactivity pattern) frequently found in neonates are rare or absent in adults. Most importantly, the vast majority of adult clonotypes are absent from the neonatal repertoire. These findings indicate that, at a developmental stage when the B-cell repertoire contains at least 10(6) clonotypes, the repertoire of genetically identical individuals is shared. This is consistent with a diversification process that is highly patterned and genetically determined. Furthermore, because 12- to 14-day-old neonates exhibit a diversified but definable hemagglutinin-specific B-cell repertoire, this experimental system should enable precise analyses of genetic and environmental influences on repertoire expression.

Age Factors↗
PubMed1978

Individual antigen-specific T lymphocytes: helper function in enabling the expression of multiple antibody isotypes.

In recent years antigen-specific T cells have been shown to be capable of mediating a number of diverse functions in collaboration with B cells in humoral immune responses. One of the more intriguing roles attributed to helper T cells is the promotion of the synthesis of multiple immunoglobulin isotypes by B cells in T-dependent antibody responses. The experiments presented in this report were carried out to determine if an individual antigen-specific T lymphocyte has the capability to enable the production of antibodies of multiple immunoglobulin heavy chain isotypes. We describe an experimental system which allows for the isolation and antigenic stimulation of individual helper T cells in a splenic environment which provides an excess of primary B cells for collaboration with isolated T lymphocytes. Employing this system we have demonstrated that an individual antigen-specific T lymphocyte, specific for the PR8 strain of influenza virus, has the capacity to enable primary B-cell PR8-specific antibody responses of more than a single immunoglobulin isotype. The implications made by these studies regarding the problem of genetic restrictions regulating T-cell-B-cell interaction is discussed.

Antibody Formation↗
PubMed1978

The diversity of the influenza-specific primary B-cell repertoire in BALB/c mice.

The primary immune response of BALB/c mice to influenza (PR8) hemagglutinin (HA), a complex protein antigen, has been examined by the splenic focus assay, and the resulting monoclonal anti-HA antibodies have been characterized by their reactivity with heterologous viruses. The analysis of the primary B-cell response to HA revealed marked differences from responses previously defined for haptenic determinants. There were following differences: (a) the frequency of HA-specific B cells in both conventional and germ-free BALB/c mice was 1 in 1.0-1.5 X 10(5) splenic B cells, which is substantially lower than the frequency of B cells responsive to various simple haptenic determinants; (b) monoclonal anti-HA antibodies were predominantly of the IgA or IgM isotypes instead of IgG, which dominates antihapten responses; and (c) after immunization, the frequency of anti-HA-specific B cells increases by 10- to 50-fold, which is much greater increase than that observed after immunization with haptenic determinants. Fine specificity analysis of primary monoclonal HA-specific antibodies revealed extensive diversity and a considerable overlap with the specificities obtained from immune mice. Given the low overall frequency of HA-specific B cells, it could be calculated that the representation of most HA-specific clonotypes within the B-cell repertoire could not exceed 1 in 10(7) B cells. These findings indicate that the primary B-cell clonotype repertoire is extremely diverse and largely antigen independent in its generation.

Animals↗
PubMed1978

Differential expression of an equivalent clonotype among BALB/c and C57BL/6 mice.

The primary anti-phosphorylcholine (PC) response in BALB/c, C57BL/6, and congenic and recombinant inbred strains of these parental types has been examined in the splenic focus system. The frequencies of PC-specific precursors were shown to vary among these strains from 2 to 20 precursors per 10(6) splenic B cells. The distribution of these frequencies suggests that elements closely linked to or within the major histocompatibility complex may play a role in the determination of this parameter, although additional experiments are necessary to adequately assess this possibility. Moreover, all strains tested, regardless of immunoglobulin allotype, expressed monoclonal antibodies indistinguishable from the TEPC 15 myeloma protein (T15) clonotype. Further, the frequency of this clonotype in a given strain did not appear related to allotype, since both high and low T15 frequencies were found among strains of either the BALB/c (a(1)) or C57BL/6 (a(2)) allotype. The examination of normal serum for the T15 idiotype, however, revealed that only mice of the BALB/c allotype (a(1)) expressed the T15 idiotype in detectable quantities. After immunization with Diplococcus pneumoniae, sera from mice of the a(1) allotype consistently contained large quantities of the T15 idiotype, whereas sera from mice of the a(2) allotype exhibited various degrees of cross-reactivity with anti-T15 antibody. These results suggest that: (a) the allotype of an individual, although closely related to serum levels of an idiotype, is unrelated to the proportion of the precursor population which expresses that idiotype and; (b) the serum expression of a given idiotype may reflect regulatory processes, which act either during or before antigenic stimulation, rather than the actual clonotype representation in the repertoire. These findings indicate that distinctions must be made between the expression of idiotypic determinants within precursor B-cell populations and elements which regulate the subsequent appearance of those idiotypes in serum antibodies.

Animals↗
PubMed1977

Idiotype-specific neonatal suppression of phosphorylcholine-responsive B cells.

The effect on neonatal anti-idiotypic suppression on the expression of B cells of the T15 clonotype has been investigated at the level of individual clonal precursor cells. The results indicate that B cells of the T15 clonotype are almost completely eliminated from the repertoire for four months after neonatal injection of allogeneic anti-idiotypic serum. The degree of this suppression is dependent on the amount of anti-idiotypic antibody administered and is less profound if anti-idiotypic antibody is given after the first week of life. No suppression was observed when anti-idiotypic antisera were administered to mice 30 days of age or older, which may indicate that immature B cells are the population most susceptible to suppression. However, since suppression could be reversed by administration of T15 myeloma protein several days after injection of anti-idiotype, the inability to suppress adult BALB/c mice may have been due to the high level of T15 idiotype normally present in their serum. Finally, phosphorylcholine-responsive B cells of identifiable clonotypes other than T15, even a clonotype sharing antigen-combining site determinants with T15, appear unaffected by anti-T15 suppression.

Aging↗