bluuebunny/crossref_metadata_2025 huggingface dataset:
Very late activation antigens (VLA) are human leukocyte-neuronal crossreactive cell surface antigens.
Authors: Pischel K D , Bluestein H G , Woods V L
Published: June 2004

The antigenic relationship between human neuronal and lymphocyte cell surface antigens has been analyzed using heteroantisera raised against human peripheral blood mononuclear cells (PBMC). The specificities of the crossreactive antigens were examined by immunoprecipitation of 125I-labeled SK-N-SH cultured neuronal cells using rabbit anti-PBMC (RAPBMC) sera and compared to known specificities using mAb. The predominant reactivity of each rabbit antiserum tested against SK-N-SH cells was with three molecules of 130,000, 160,000, and 180,000 Mr. These three chains comigrated with three molecules precipitated with the very late activation antigen (VLA)-specific mAb A-1A5. Sequential precipitations with mAb A-1A5 established that the three RAPBMC-precipitated bands were members of the VLA complex. This was confirmed by two-dimensional PAGE of the RAPBMC and A-1A5 immunoprecipitates, which were indistinguishable from one another. The two-dimensional pattern was more complex than was anticipated from the heterodimeric model of VLA chain association, and suggests an additional 130,000 Mr component of VLA. The three chains of the VLA complex precipitated by RAPBMC or mAb A-1A5 from SK-N-SH neurons closely resembled the VLA pattern present on activated T cells, including the 180,000 Mr activation-specific alpha 1 chain recognized by mAb TS2/7. Normal brain cell membranes also contain VLA molecules that are precipitated by RAPBMC and mAb A-1A5. Thus the VLA complex provides potentially important shared immunogens on human neurons and T cells.
A new HLA-linked T cell membrane molecule, related to the beta chain of the clonotypic receptor, is associated with T3.
Authors: Bushkin Y , Posnett D N , Pernis B , Wang C Y
Published: June 2004

The 38 kD molecule is noncovalently associated with beta 2 microglobulin (beta 2m)-free HLA heavy chain-like molecule, and thus forms a second heterodimer distinct from the clonotypic alpha/beta T cell receptor expressed by the same clone of leukemia cells. This second heterodimer (38 kD/HLA) is variably expressed and appears to be associated with the T3 molecule. We suggest, therefore, that it has a functional role in T cell activation.
Blockade of clearance of immune complexes by an anti-F(cγ) receptor monoclonal antibody
Authors: Clarkson SB , Kimberly RP , Valinsky JE , Witmer MD , Bussel JB , Nachman RL , Unkeless JC
Published: June 2004

Clearance of immune complexes by the mononuclear phagocyte system is important for maintaining normal host defenses against bacterial and viral assault (1), but also contributes to the pathogenesis of a variety of immune- mediated diseases . For example, removal from the circulation of IgG-coated erythrocytes and platelets by the MPS is the sine qua non of immune-mediated cytopenias (2, 3). On the other hand, abnormally decreased removal by the MPS of smaller, soluble immune complexes may play a role in the pathogenesis of immune complex-mediated tissue damage found in such autoimmune diseases as SLE (4).

Although the physicochemical nature and the size of immune complexes can influence rates of clearance and sites of deposition (reviewed in 5), interactions between immune complexes and the MPS in vivo are poorly understood. The inability to directly measure binding or internalization of immune complexes by cells in the liver and spleen has made the analysis of the molecular basis of immune complex clearance very difficult . Receptors for the Fc portion of IgG (FcγR) and for complement (CR) undoubtedly play a role in the removal of immune complexes, but the relative importance of these receptors is not known.
Interleukin 1 of the central nervous system is produced by ameboid microglia.
Authors: Giulian D , Baker T J , Shih L C , Lachman L B
Published: June 2004

By screening specific populations of rat brain cells, we found that ameboid microglia secrete an 18 kD peptide with IL-1 biological activity. The IL-1 activity released by microglia was found to be identical to rat macrophage IL-1 on fractionation by gel filtration and high pressure liquid anion-exchange chromatography, and it was neutralized by an antiserum specific for murine IL-1. When added to astroglia grown in culture, microglial IL-1 increased the cell number of five- to sevenfold, and increased astroglial incorporation of [3H]thymidine by three- to fivefold. We propose that the proliferation of astroglia in specific brain regions may be regulated by the signaled release of IL-1 from activated microglial cells.
Transgenic mice with mu and kappa genes encoding antiphosphorylcholine antibodies.
Authors: Storb U , Pinkert C , Arp B , Engler P , Gollahon K , Manz J , Brady W , Brinster R L
Published: June 2004

Transgenic mice were produced that carried in their germlines rearranged kappa and/or mu genes with V kappa and VH regions from the myeloma MOPC-167 kappa and H genes, which encode anti-PC antibody. The mu genes contain either a complete gene, including the membrane terminus (mu genes), or genes in which this terminus is deleted and only the secreted terminus remains (mu delta mem genes). The mu gene without membrane terminus is expressed at as high a level as the mu gene with the complete 3' end, suggesting that this terminus is not required for chromatin activation of the mu locus or for stability of the mRNA. The transgenes are expressed only in lymphoid organs. In contrast to our previous studies with MOPC-21 kappa transgenic mice, the mu transgene is transcribed in T lymphocytes as well as B lymphocytes. Thymocytes from mu and kappa mu transgenic mice display elevated levels of M-167 mu RNA and do not show elevated levels of kappa RNA, even though higher than normal levels of M-167 kappa RNA are detected in the spleen of these mice. Approximately 60% of thymocytes of mu transgenic mice produce cytoplasmic mu protein. However, despite a large amount of mu RNA of the membrane form, mu protein cannot be detected on the surface of T cells, perhaps because it cannot associate with T cell receptor alpha or beta chains. Mice with the complete mu transgene produce not only the mu transgenic mRNA but also considerably increased amounts of kappa RNA encoded by endogenous MOPC-167 like kappa genes. This suggests that B cells are selected by antigen (PC) if they coexpress the mu transgene and appropriate anti-PC endogenous kappa genes. Mice with the mu delta mem gene, however, do not express detectable levels of the endogenous MOPC-167 kappa mRNA. Like the complete mu transgene, the M-167 kappa transgene also causes amplification of endogenous MOPC-167 related immunoglobulins; mice with the kappa transgene have increased amounts of endogenous MOPC-167-like mu or alpha or gamma in the spleen, all of the secreted form. Implications for the regulation of immunoglobulin gene expression and B cell triggering are discussed.
Isolation of a lipopolysaccharide-binding acute phase reactant from rabbit serum.
Authors: Tobias P S , Soldau K , Ulevitch R J
Published: June 2004

This report describes the purification of an acute phase reactant from acute phase rabbit serum, which endows normal serum with the properties of acute phase serum, insofar as LPS is concerned. The acute phase reactant is referred to as LPS-binding protein, or LBP. LBP was purified approximately 2,000-fold by chromatography of acute phase serum on Bio-Rex 70 and Mono-Q resins. The resulting preparation consisted of two glycoproteins having molecular weights of 60,500 and 58,000; the two were obtained in a variable ratio, usually near 10:1, respectively. After separation by SDS-PAGE, the N-terminal 36 amino acid sequences of the two proteins were identical. From the N-terminal sequence, as well as other properties of LBP, LBP appears to be unrelated to any known acute phase reactants. The direct interaction of LPS and LBP was inferred from two types of evidence: first, immunoprecipitation of [3H]LPS from APRS by anti-LBP sera; and second, by the 125I-labeling of LBP when APRS-containing 125I-labeled 2-(p-azidosalicylamido)ethyl 1,3'-dithiopropionyl-LPS was photolysed. The data presented here support the concept that the 60-kD glycoprotein we have termed LBP is a newly recognized acute phase reactant that may modulate the biochemical and biologic properties of LPS in vivo.
Dissection of the lymphokine-activated killer phenomenon. Relative contribution of peripheral blood natural killer cells and T lymphocytes to cytolysis.
Authors: Phillips J H , Lanier L L
Published: June 2004

In vitro culture of human peripheral blood lymphocytes in IL-2 results in the generation of cytotoxic cells that can lyse fresh and cultured solid tumor cells, as well as hematopoietic tumor cell lines, without deliberate immunization or MHC restriction. This has been referred to as the lymphokine activated killer (LAK) phenomenon. Here, we show that the majority of this activity is mediated by NK cells that express the Leu-19 (NKH-1) antigen, but do not express CD3. The precursor of this effector population also expressed the phenotype CD3-, Leu-19+. Peripheral blood CD3+ T lymphocytes contributed little to the LAK phenomenon, although low levels of non-MHC restricted cytotoxicity against hematopoietic tumor cell targets were mediated by a subset of CD3+ T lymphocytes that coexpressed the Leu-19 antigen. These studies clearly indicated that the LAK phenomenon is not mediated by a unique LAK cell, but is mediated mainly by IL-2-activated peripheral blood NK cells.
Bystander help in primary immune responses in vivo.
Authors: Jensen P E , Kapp J A
Published: June 2004

We evaluated the requirement for hapten-carrier linkage in the primary, T cell-dependent antibody response in vivo. Mice immunized with mixtures containing nonimmunogenic and immunogenic proteins developed antibody that was specific for determinants present on the nonimmunogenic carrier. Therefore, hapten-carrier linkage was not necessary for the generation of primary antibody responses. The magnitude of the bystander response was a function of the immunogenicity of the coimmunogen and the quantity of determinant-specific B cells available for activation. Interestingly, the kinetics of the bystander response, in contrast to the cognate response, were not accelerated in the presence of primed Th cells. Adoptive recipients reconstituted with primed Th cells developed accelerated cognate but not bystander antibody response, as compared with unprimed recipients. This phenomenon may reflect a regulatory mechanism invoked to limit the potentially harmful effects of nonspecific help. It was observed that while animals are tolerant to immunization with mouse (self) hemoglobin, immunization with a mixture containing mouse hemoglobin plus fowl gamma globulin resulted in the production of hemoglobin-binding autoantibodies. Thus bystander help induced by coimmunization may serve as a model for the induction of autoantibodies during normal immune responses in vivo.
The T cell repertoire for recognition of a phylogenetically distant protein antigen. Peptide specificity and MHC restriction of staphylococcal nuclease-specific T cell clones.
Authors: Finnegan A , Smith M A , Smith J A , Berzofsky J , Sachs D H , Hodes R J
Published: June 2004

Previous studies (1) have indicated that the repertoire of murine T cells specific for a potentially complex protein antigen is in fact specific for a limited number of antigenic epitopes on that antigen in association with a given Ia molecule. Since those studies generally analyzed responses to antigens that differ in only a few amino acids from homologous murine molecules, it was possible that tolerance to self proteins was responsible for the limited T cell repertoire seen in responses to closely related proteins. It was therefore of interest to determine whether T cell recognition of a structurally and phylogenetically more distant protein molecule would also show specificity for a limited number of immunodominant peptides on that molecule. A series of experiments was designed to study the antigen fine specificity and MHC restriction of T cell clones specific for the bacterially derived antigen staphylococcal nuclease (Nase). T cell clones generated in (H-2b X H-2a)F1 (B6AF1) T cells were shown to be specific for Nase and to be restricted by either Ab alpha Ab beta or Ek alpha Ek beta. The fine specificity of these clones was then analyzed using cyanogen bromide and tryptic fragments and a series of overlapping 20-amino-acid synthetic peptides corresponding to and spanning the entire sequence of the Nase molecule. Two Ab alpha Ab beta-restricted clones were highly responsive to peptide 91-110, and not to other synthetic Nase peptides. In contrast, seven Ek alpha Ek beta-restricted clones were consistently responsive to peptide 81-100 and not to 91-110 or to other Nase peptides. Certain of these Ek alpha Ek beta-restricted T cells expressed an interesting crossreactivity, in that they responded to peptide 51-70 as well as to 81-100, although the response to 51-70 was characterized by a markedly shifted dose-response curve, indicating a reduced efficiency of activation by this peptide. Analysis of the amino acid sequences of these regions indicates that this unexpected crossreaction may have a structural basis. A single Nase-specific T cell line generated from BALB/c T cells was, in contrast to any of the B6AF1 clones studied, responsive only to peptide 61-80 and not to other peptides, including 81-100 or 91-110. Collectively, these findings show that Nase-specific T cells are responsive to discrete Nase peptides. Moreover, the present findings suggest that in T cell recognition of a complex and highly foreign protein antigen, a limited number of peptide epitopes are preferentially recognized by T cells in association with a given Ia molecule.
Long-term humoral unresponsiveness in vivo, induced by treatment with monoclonal antibody against L3T4.
Authors: Goronzy J , Weyand C M , Fathman C G
Published: June 2004

mAbs directed against the L3T4 molecule administered in vivo caused a severe and long lasting helper cell depletion in mice. Regeneration of the L3T4+ subpopulation occurred gradually (2-3 mo) after a single antibody treatment. Experiments were designed to examine the humoral immunocompetence of such anti-L3T4-treated animals during and after regeneration of the L3T4+ T cell subset. The animals were injected with anti-L3T4, immunized with soluble antigen, and challenged with antigen every 2 wk. Antibody responses to two antigens, sperm whale myoglobin (SpWMb) and KLH, which differ with regard to their immunogenicity, were compared. The lack of humoral immune responsiveness to either of these two antigens shorty after anti-L3T4 treatment responsiveness to either of these two antigens shortly after anti-L3T4 treatment was probably due to clonal depletion. The anti-L3T4-induced immunosuppressive effect on antibody production seemed to be determined in part by the preexisting T cell repertoire, as was suggested by the recovery of responsiveness to the highly immunogenic antigen KLH and the transient inhibitory effect of anti-L3T4 treatment in primed animals. The regenerating L3T4+ T cell subpopulation was relatively incompetent in initiating B cell responses. More than 40% of the L3T4+ T cell compartment had to recover to provide help for the production of anti-KLH antibodies, whereas elimination of 90% of the L3T4+ helper cells did not inhibit a primary anti-KLH response. Evidence for a heterogeneous composition of the L3T4+ subset came from experiments using rIL-2 in vivo. The addition of rIL-2 during early helper cell depletion improved the recovery of the humoral responsiveness without apparently affecting the kinetics of the regeneration of L3T4+ T cells. Interestingly, humoral unresponsiveness to the weakly immunogenic antigen SpWMb persisted for at least 120 d. This long lasting unresponsiveness could not be explained by clonal depletion, and suggested as one possibility that the presence of antigen during regeneration of the L3T4+ helper cell population may have influenced the ultimate T cell repertoire.
Cytotoxic T lymphocytes against disease-associated determinant(s) in ankylosing spondylitis.
Authors: Geczy A F , McGuigan L E , Sullivan J S , Edmonds J P
Published: June 2004

Cytotoxic T lymphocytes, induced by stimulating the PBMC of an HLA-B27+ normal individual (B27+, AS-) with the PBMC of an HLA-identical sibling suffering from ankylosing spondylitis (AS) (B27+, AS+), specifically lyse B27+, AS+ PBMC but not PBMC from HLA-27+ or B27-, AS- normal controls, or from HLA-B27- AS patients (B27-,AS+). CTL of similar specificity can also be raised by immunizing in vitro B27+,AS- cells with autologous cells modified by cross-reactive bacterial antigens. These results suggest that CTL can recognize certain bacterial antigens in association with HLA-B27 and that this interaction may lead to an inflammatory episode during the initial stages of the disease.
T cell-mediated hepatitis in mice infected with lymphocytic choriomeningitis virus. Liver cell destruction by H-2 class I-restricted virus-specific cytotoxic T cells as a physiological correlate of the 51Cr-release assay?
Authors: Zinkernagel R M , Haenseler E , Leist T , Cerny A , Hengartner H , Althage A
Published: June 2004

A model for immunologically T cell-mediated hepatitis was established in mice infected with lymphocytic choriomeningitis virus (LCMV). The severity of hepatitis was monitored histologically and by determination of changes in serum levels of the enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH), and alkaline phosphatase (AP). Kinetics of histological disease manifestations, increases of liver enzyme levels in the serum, and cytotoxic T cell activities in livers and spleens all correlated and were dependent upon several parameters: LCMV-isolate; LCMV-WE caused extensive hepatitis, LCMV-Armstrong virtually none. Virus dose. Route of infection; i.v. or i.p. infection caused hepatitis, whereas infection into the footpad did not. The general genetic background of the murine host; of the strains tested, Swiss mice and A-strain mice were more susceptible than C57BL or CBA mice; BALB/c and DBA/2 mice were least susceptible. The degree of immunocompetence of the murine host; T cell deficient nu/nu mice never developed hepatitis, whereas nu/+ or +/+ mice always did. B cell-depleted anti-IgM-treated mice developed immune-mediated hepatitis comparably or even more extensively than control mice. Local cytotoxic T cell activity; mononuclear cells isolated from livers during the period of overt hepatitis were two to five times more active than equal numbers of spleen cells. Adoptive transfer of nylon wool-nonadherent anti-Thy-1.2 and anti-Lyt-2 plus C-sensitive, anti-L3T4 plus C-resistant lymphocytes into irradiated mice preinfected with LCMV-WE caused a rapid time- and dose-dependent linear increase of serum enzyme levels. This increase was caused by adoptive transfer of lymphocytes if immune cell donors and recipient mice shared class I, but not when they shared class II histocompatibility antigens. The donor cell dose-dependent increase of these enzymes was first measurable 6-18 h after transfer with 2 X 10(8) cells or 3 X 10(6) cells, respectively. The time-dependent increase caused by the adoptive transfer of 1-2 X 10(8) cells was strictly linear during a period of up to 25-40 h. These results indicate single-hit kinetics of liver cell death and suggest that effector T cells destroy infected liver cells via direct contact rather than via soluble toxic mediators. The results may represent the best in vivo correlate of the in vitro 51Cr-release assay that has been analyzed so far, and strongly support the view that antiviral cytotoxic T cells are directly cytolytic in vivo.(ABSTRACT TRUNCATED AT 400 WORDS)
A recombinant murine granulocyte/macrophage (GM) colony-stimulating factor derived from an inducer T cell line (IH5.5). Functional restriction to GM progenitor cells.
Authors: Kajigaya S , Suda T , Suda J , Saito M , Miura Y , Iizuka M , Kobayashi S , Minato N , Sudo T
Published: June 2004

The cDNA for the murine granulocyte/macrophage colony-stimulating factor (GM-CSF) was cloned from a cDNA library obtained from a murine T cell line, IH5.5, by using two synthetic probes that encoded two parts of the GM-CSF from murine lung. The cDNA inserted into the plasmid vector pcDV1 was transfected into monkey COS-1 cells and the conditioned medium was used to investigate the hemopoietic activities of the resultant product, recombinant GM-CSF (rGM-CSF), by means of various colony assays. rGM-CSF stimulated only neutrophil/macrophage colonies in the cultures of murine normal bone marrow and fetal liver cells. No other colony stimulating activities (CSA) were seen in the preparation including burst-promoting activity, eosinophil-CSA, megakaryocyte-CSA and mast cell-CSA. rGM-CSF could not support colony formation of 5-fluorouracil-treated mouse spleen cells, in which only the primitive population of stem cells survived. However, after culture of these cells with PWM-spleen cell-conditioned medium (PWM-SCM), the colonies consisting of blast cells were formed. These blast cells could now be induced to form neutrophil/macrophage colonies in the presence of rGM-CSF. Pure neutrophil colonies, pure macrophage colonies, as well as mixed neutrophil/macrophage colonies, were formed from these single blast cells in the presence of rGM-CSF by micromanipulation. rGM-CSF did not act on pluripotent hemopoietic stem cells, but did act directly and selectively on neutrophil/macrophage progenitors. Moreover, striking heterogeneities were noted in the size of the colonies and the proportion of components. GM-CSF is, therefore, considered to play a noninstructive role in the differentiation of the GM pathway.
Functional analysis of influenza-specific helper T cell clones in vivo. T cells specific for internal viral proteins provide cognate help for B cell responses to hemagglutinin.
Authors: Scherle P A , Gerhard W
Published: June 2004

We compared the effects of adoptively transferred Th cell clones specific for the influenza hemagglutinin (HA), matrix (M), or nucleoprotein (NP) on the antibody response of nude mice infected with A/PR/8/34 influenza virus. We show that the production of antibodies to the HA absolutely requires the presence of virus-specific Th cells. Further, transfer of a Th clone specific for the internal proteins, M or NP, was as effective as was transfer of an HA-specific clone in supporting an antibody response to the HA. With each of the clones, the kinetics of the response were accelerated by approximately 3 d compared with the antibody response of normal BALB/c mice. The HA- and M-specific clones supported an isotype switch from IgM to IgG and IgA similar to that which occurs during a normal antibody response. Finally, as shown by coinfection experiments, the response required a cognate T-B interaction whether the determinants recognized by the Th and B cell are located on the same viral protein or on different viral proteins within the same virus particle. The implications of these findings for understanding the T-B interactions that occur during an effective antiviral antibody response are discussed.
Quantitative variations of the C3b/C4b receptor (CR1) in human erythrocytes are controlled by genes within the regulator of complement activation (RCA) gene cluster.
Authors: Rodriguez de Cordoba S , Rubinstein P
Published: June 2004

The genetic relationships of quantitative and structural variations of the C3b/C4b receptor (CR1) in human erythrocytes have been analyzed in informative families. Our results demonstrate the existence of multiple discrete quantitative variations of CR1 controlled by a locus, C3bRQ, closely linked to the CR1 structural locus, C3bR. Since the amounts of CR1 produced by each C3bR allele are shown to be independently regulated, we propose that a cis-acting genetic mechanism controls the level of expression of the C3bR alleles, and that this quantitative control plays a major, if not the sole, role in determining the total amounts of CR1 on normal human erythrocytes.
Enhanced reactive lysis of paroxysmal nocturnal hemoglobinuria erythrocytes. Studies on C9 binding and incorporation into high molecular weight complexes.
Authors: Rosenfeld S I , Jenkins D E , Leddy J P
Published: June 2004

As part of a broader analysis of the mechanism(s) by which the most sensitive (type III) paroxysmal nocturnal hemoglobinuria (PNH) erythrocytes are excessively sensitive to reactive lysis by isolated C5b6, C7, C8, and C9, we have compared type III PNH (PNH-III) and normal human E in respect to both total specific binding of 125I-C9 and the proportion of cell-bound C9 appearing in high molecular weight (HMW) complexes. In a previous report, we found that after exposure to purified C5b6 and 125I-C7, specific C7 binding and, by implication, EC5b-7 formation were equal for PNH-III E and normal E. In the present study, C8-dependent binding of 125I-C9 to PNH-III EC5b-7 and normal EC5b-7 was also similar, although lysis of the PNH-III E was up to five times greater; that is, PNH-III E required fewer bound C9 molecules to produce an effective lytic site than did normal E. To quantify radioactivity in monomeric and HMW forms of membrane-bound C9, lysed and unlysed E were subjected to low ionic strength buffers to convert all E to ghosts. These ghosts were solubilized in 0.1 or 2% SDS (without reduction) and electrophoresed on 2.4-11% polyacrylamide gradient gels followed by autoradiography and densitometric scanning. With 0.1% SDS, broad, heterodisperse zones of HMW C9 were recovered from both PNH and normal ghosts; the amounts of C9 incorporated into the HMW complexes were similar for PNH-III E and normal E. In selected experiments, 125I-C7 could be shown in these same HMW bands. When membranes were solubilized in 2% SDS, the overall proportion of HMW C9 complexes compared with dimer and monomer C9 was reduced on both PNH and normal membranes. In many, but not all experiments, more of the highest mol wt C9 complexes were detected from PNH-III E membranes solubilized in 2% SDS than from normal or PNH-II E membranes similarly treated. When antibody-sensitized E were lysed by purified C1-C9, PNH-III EA bound far more C9 than did normal EA, and both lysis and C9 incorporation into HMW complexes were markedly and proportionately increased over normal; however, lytic efficiency of 125I-C9 bound to PNH EA was equal to or less than that bound to normal EA.(ABSTRACT TRUNCATED AT 250 WORDS)
Analysis of multiple restriction fragment length polymorphisms of the gene for the human complement receptor type I. Duplication of genomic sequences occurs in association with a high molecular mass receptor allotype.
Authors: Wong W W , Kennedy C A , Bonaccio E T , Wilson J G , Klickstein L B , Weis J H , Fearon D T
Published: June 2004

Human CR1 exhibits an unusual form of polymorphism in which allotypic variants differ in the molecular weight of their respective polypeptide chains. To address mechanisms involved in the generation of the CR1 allotypes, DNA from individuals having the F allotype (250,000 Mr), the S allotype (290,000 Mr), and the F' allotype (210,000 Mr) was digested by restriction enzymes, and Southern blots were hybridized with CR1 cDNA and genomic probes. With the use of Bam HI and Sac I, an additional restriction fragment was observed in 20 of 21 individuals having the S allotype with no associated loss of other restriction fragments. Southern blot analysis with a noncoding genomic probe derived from the S allotype-specific Bam HI fragment showed hybridization to this fragment and to two other fragments that were also present in FF individuals. Thus, an intervening sequence may be repeated twice in the F allele and three times in the S allele. A restriction fragment length polymorphism (RFLP) unique to two individuals expressing the F' allotype was seen with Eco RV, but the absence of persons homozygous for this rare allotype prevented further comparisons with the F and S allotypes. Analysis of the CR1 transcripts associated with the three CR1 allotypes indicated that these differed by 1.3-1.5 kb and had the same rank order as the corresponding allotypes. Taken together, these findings suggest that the S allele was generated from the F allele by the acquisition of additional sequences, the coding portion of which may correspond to a long homologous repeat of approximately 1.4 kb that has been identified in CR1 cDNA. We saw two other RFLPs with Hind III and Pvu II that were in linkage dysequilibrium with the Bam HI-Sac I RFLPs associated with the S allotype, and a third polymorphism was seen with Eco RI that was not in linkage dysequilibrium with the other polymorphisms. Thus, 10 commonly occurring CR1 alleles can be defined, making this locus a useful marker for the long arm of chromosome 1 to which the CR1 gene maps.
Immunity in human schistosomiasis mansoni. Regulation of protective immune mechanisms by IgM blocking antibodies.
Authors: Khalife J , Capron M , Capron A , Grzych J M , Butterworth A E , Dunne D W , Ouma J H
Published: June 2004

After the demonstration of blocking antibodies during rat experimental schistosomiasis, the existence of such factors was investigated in human schistosomiasis. The depletion, in sera from S. mansoni-infected patients, of a given isotype (IgM) either by protein A-Sepharose (PAS) absorption or by fast protein liquid chromatography (FPLC) induced a significant increase in IgG-mediated killing of S. mansoni schistosomula by human eosinophils. Inhibition experiments showed that IgM-enriched fractions (PAS effluents) were able to inhibit eosinophil-dependent cytotoxicity mediated by IgG fractions (total sera or PAS eluates). Both IgG and IgM antibodies from infected human sera immunoprecipitated antigens of 30,000-40,000 Mr in the labeled detergent extracts of schistosomulum surface. The specificity of IgG and IgM for the 38,000 Mr antigen was suggested by competition experiments using two radiolabeled mAbs (IPLSm1, IPLSm3) directed against this antigen. Moreover, crossinhibition between IgG and IgM antibodies for the Mr 38,000 antigen could be directly demonstrated. The in vivo relevance of such IgM blocking antibodies in the context of human immunity to schistosomiasis was evaluated in two groups of children classified as resistant or susceptible to posttreatment reinfection. IgM antibodies specifically directed against the 38,000 Mr antigen were measured by a capture assay. The mean levels of IgM antibodies were significantly higher in the susceptible than in the resistant group both before and after treatment. These results are consistent with the idea that immunity to schistosomiasis could be attributable not only to the existence of antibodies with defined effector function, but also to the absence of blocking antibodies. The description of the existence in human schistosomiasis of antibody isotypes blocking the effector response against defined surface targets might lead to a new understanding of the mechanisms regulating immunity to reinfection against schistosomes and possibly other parasites.
Radiation-induced, immunologically mediated regression of an established tumor as an example of successful therapeutic immunomanipulation. Preferential elimination of suppressor T cells allows sustained production of effector T cells.
Authors: North R J
Published: June 2004

The results of this study confirm results published by others by showing that sublethal whole-body irradiation of mice bearing immunogenic tumors can result in complete tumor regression. The results show, in addition, that irradiation-induced tumor regression can be prevented by infusion, after irradiation, of Ly-1+,2-,L3T4+ suppressor T cells from the spleens of donors bearing an established tumor, but not by infusion of normal spleen cells. This evidence, plus the demonstration that irradiation fails to cause regression of tumors growing in immunocompetent mice, is consistent with the hypothesis that irradiation-induced regression is immunologically mediated, and that it depends on the ability of irradiation to preferentially eliminate suppressor T cells. By using passive transfer assays to measure the production of effector T cells and suppressor T cells against time of tumor growth, it was shown that irradiation of tumor-bearing mice on day 5 of tumor growth resulted in a failure to generate suppressor T cells on the one hand, and in a sustained production, effector T cells on the other. In other words, irradiation prevented the concomitant antitumor immune response from being downregulated by suppressor T cells. However, giving radiation on day 1 of tumor growth, in contrast to giving it 3-6 d later, caused immunodepression and enhancement of tumor growth. This is in keeping with published evidence showing that, whereas resting effector T cells are highly radiosensitive, antigen-activated effector T cells are relatively radioresistant. It is suggested that the radioresistance of activated effector T cells, coupled with the radiosensitivity of activated suppressor T cells, is the reason for the selectivity of ionizing radiation for suppressor T cells and why a tumor needs to be palpable to undergo regression in response to radiation therapy.
Direct T helper-B cell interactions induce an early B cell activation antigen.
Authors: Crow M K , Jover J A , Friedman S M
Published: June 2004

We have explored the consequences for the B cell of cognate interaction with T cells. Early expression of the B cell-restricted cell surface activation antigen, BLAST-2, has been used as an assay system to measure direct T-B cell collaboration. BLAST-2 is preferentially expressed by allogenic B cells cultured with MHC class II antigen-restricted Th clone cells matched to the DR specificity of the target B cells. B cells cultured with DR-mismatched allospecific Th cells express minimal BLAST-2. Th cell-induced BLAST-2 expression appears to be accessory cell independent and occurs as early as 8 h after initiation of culture, with peak expression at 18 h. Direct T-B cell contact, rather than Th-derived lymphokines, provides the most efficient stimulus for BLAST-2 expression. Crosslinking of sIg on B cells is a poor stimulus for BLAST-2 expression. The BLAST-2 assay permits the evaluation of early events associated with B cell activation through cognate interactions, and may facilitate subsequent studies of the mechanism of B cell differentiation.
T cell clones specific for an amphipathic alpha-helical region of sperm whale myoglobin show differing fine specificities for synthetic peptides. A multiview/single structure interpretation of immunodominance.
Authors: Cease K B , Berkower I , York-Jolley J , Berzofsky J A
Published: June 2004

The T cell response to sperm whale myoglobin in the H-2d haplotype has been shown to be largely focused on a limited region around glutamic acid 109 recognized in association with I-Ad. T cell clones 9.27 and 1.2 have been previously (4, 5) shown to reflect this specificity and MHC restriction. In this study we have used a panel of synthetic peptides from the region 102-118 of myoglobin to characterize the specificities of these representative clones. The segment from 106-118 was found to represent a consensus region for recognition by both clones. However, we saw significant differences between clones in the hierarchy of responsiveness to peptides within the panel. In as much as the peptide and the I-Ad molecule remain constant, these differences derive from differences in how each T cell receptor interacts with the antigen. This peptide segment is an amphipathic alpha helix in native myoglobin, meaning that one side is hydrophobic and the other hydrophilic. It is one of the prototype cases that led us to find that amphipathic helices constitute the majority of immunodominant sites recognized by helper T cells (1). It is likely that the peptide will refold into an amphipathic helix stabilized by the interface at the surface of the presenting cell. When such secondary conformation is considered, these data are consistent with a model of multiple T cell specificities arising from multiple views of a single antigen conformation at a single Ia-binding site and do not require postulation of multiple conformations or binding sites. Additionally, the finding of distinct specificities suggests that the immunodominance of this site depends not on the dominance of a single clone, but on the focusing of a polyclonal response on a single region of the molecule in association with I-Ad. The immunodominance of this particular region of the protein may thus depend on intrinsic features of the site, such as potential to form an amphipathic helix, as well as extrinsic factors such as binding properties of the I-A molecule.
The Ro/SSA autoantigen as an immunogen. Some anti-Ro/SSA antibody binds IgG.
Authors: Mamula M J , Fox O F , Yamagata H , Harley J B
Published: June 2004

The rheumatic disease autoantigen, Ro/SSA, was immunogenic to a rabbit host. The heteroimmune rabbit serum bound the Ro/SSA particle in immunoblots and in an ELISA. Both the rabbit anti-Ro/SSA and a human prototype anti-Ro/SSA serum also bound IgG; and moreover, IgG inhibited both rabbit and human anti-Ro/SSA activity. Anti-IgG activity of the rabbit and human anti-Ro/SSA sera bound Ro/SSA by Western blot and solid-phase assays. In addition, purified Ro/SSA inhibited the anti-IgG activity of the anti-Ro/SSA sera from rabbit and man. Affinity purification of the IgG- and Ro/SSA-binding fractions of the rabbit anti-Ro/SSA demonstrated that both the anti-Ro/SSA and anti-IgG activities were concentrated in these fractions. These data show that Ro/SSA and IgG share epitopes that are bound by anti-Ro/SSA antibody. Inhibition experiments suggest that this antibody is found in most human anti-Ro/SSA autoimmune sera and that the epitope(s) are found in the F(ab')2 fragment of IgG.
Assembly of the prothrombin activator complex on rabbit alveolar macrophage high-affinity factor Xa receptors. A kinetic study.
Authors: McGee M P , Rothberger H
Published: June 2004

Efficient prothrombin activation occurs after assembly of factors Va, Xa, and phospholipid surface cofactor as a multimolecular complex. These components are provided by platelets and plasma within the vascular space, but molecules and membranes for prothrombin activator assembly in extravascular spaces have not been identified. In the present study, purified alveolar macrophages were found to produce high-affinity factor Xa receptors that mediate formation of enzymatic prothrombinase complexes and rapid prothrombin to thrombin conversion in the absence of exogenous factor V/Va or platelets. Thus, in reaction mixtures with alveolar macrophages cultured for 20 h in serum-free medium, the thrombin formation rate was 152 nM/min/0.66 X 10(6) cells, after adding prothrombin (1.5 microM), Ca2+ (5 mM), and factor Xa (3.7 nM). The observed Kd of factor Xa interaction with macrophage receptors is 2.1 +/- 0.94 X 10(-10) M. Kinetic analysis and inhibition studies using isolated factor V and anti-factor V antibody show that macrophage Xa receptors are functionally and antigenically similar to plasma factor V. By contrast, freshly isolated cells lacked receptors promoting prothrombin conversion at high rates. Inhibitors of protein synthesis and glycosylation, puromycin and monensin, respectively, abrogated production of Xa receptors in culture. Additionally, subcellular fractionation and enzyme-marker studies (alkaline phosphodiesterase I) indicate that internal and external membranes of alveolar macrophages have phospholipid surface cofactor activity required for prothrombinase complexes. Pulmonary surfactant is also shown to express this cofactor activity. Alveolar macrophages and surfactant comprise an efficient prothrombin activator system that is independent of plasma factor V. This system may facilitate rapid extravascular alveolar thrombin formation even at very low concentrations of factor Xa during lung defense reactions to inflammation or edema.
Molecular localization and polymorphism of HLA class II restriction determinants defined by Mycobacterium leprae-reactive helper T cell clones from leprosy patients.
Authors: Ottenhoff T H , Neuteboom S , Elferink D G , de Vries R R
Published: June 2004

MHC class II molecules carry the restriction determinants (RDs) for antigen presentation to antigen-specific Th lymphocytes. This restriction of T cell activation endows those molecules with a key role in the induction and regulation of antigen-specific immune responses. Moreover, class II molecules are the products of class II immune response (Ir) genes. The polymorphism of these Ir genes leads to genetically controlled differences in immuneresponsiveness between different individuals. An important human example is leprosy, in which HLA class II-linked Ir genes determine the immune response against Mycobacterium leprae, the causative organism of the disease. Since the immune response against M. leprae is entirely dependent on Th cells, the HLA class II-linked Ir gene products may well regulate the immune response by controlling the presentation of M. leprae antigens to Th cells. We therefore have investigated the HLA class II RD repertoire of M. leprae-reactive Th cell clones (TLC) by means of extensive panel and inhibition studies with fully class II-typed allogeneic APCs and well-defined HLA class II-specific mAbs. The TLC studied (n, 36) proliferated specifically towards M. leprae, produced IFN-gamma upon activation, and had the CD3+CD4+CD8- phenotype. The results show in the first place that the majority of the RDs for M. leprae reside on DR and not on DP or DQ molecules. This indicates a major role for DR molecules in the immune response to M. leprae and suggests that these molecules are the main products of M. leprae-specific Ir genes. Furthermore, since the expression of DR molecules is much stronger than that of DP and DQ molecules, these findings suggest that the localization of RDs for M. leprae on class II molecules correlates with the quantitative expression of these molecules. The observation that the RDs on DR molecules coded by a DR4 haplotype were situated only on those DR molecules that are known to be highest in expression can be explained in the same way. Second, four distinct RDs related with but not identical to the Dw13 allodeterminant were carried by the DR+DRw53- (alpha beta 1) molecules of a DR4Dw13 haplotype. Since the known amino acid residue differences between the allelic DR4 related Dw beta 1 chains cannot explain the observed RD-polymorphism, this observation suggests that multiple distinct RDs unique for the DR4Dw13 haplotype are expressed by these molecules. Only 2 of 36 TLC were not restricted by DR.(ABSTRACT TRUNCATED AT 400 WORDS)
Isolation and preliminary biochemical characterization of the gonococcal H.8 antigen.
Authors: Strittmatter W , Hitchcock P J
Published: June 2004

We have presented a method for the extraction and isolation of the gonococcal H.8 antigen. There was no evidence of contamination by other gonococcal proteins, phospholipids, or LPS. The purified H.8 antigen was subjected to preliminary analysis and appeared to be a proteolipid consisting of both protein and lipid components. The amino acid composition was unusual; the peptide portion of the antigen was an alanine and proline-rich molecule that lacked aromatic and sulfur-containing amino acids. The overall amino acid composition is hydrophobic. A lipid constituent was also identified; it was made up of at least two lipid components, which were unique to the H.8 molecule. The chemical nature of the association of the protein and lipid is presently unknown, but it is clearly a tenacious one.
Multiple monoclonal B cell expansions and c-myc oncogene rearrangements in acquired immune deficiency syndrome-related lymphoproliferative disorders. Implications for lymphomagenesis.
Authors: Pelicci P G , Knowles D M , Arlin Z A , Wieczorek R , Luciw P , Dina D , Basilico C , Dalla-Favera R
Published: June 2004

AIDS (acquired immune deficiency syndrome) and ARC (AIDS-related complex) are associated with a spectrum of lymphoproliferative disorders ranging from lymphadenopathy syndrome (LAS), an apparently benign polyclonal lymphoid hyperplasia, to B cell non-Hodgkin's lymphoma (B-NHL), i.e., malignant, presumably monoclonal B cell proliferations. To gain insight into the process of lymphomagenesis in AIDS and to investigate a possible pathogenetic relationship between LAS and NHL, we investigated the clonality of the B or T lymphoid populations by Ig or T beta gene rearrangement analysis, the presence of rearrangements involving the c-myc oncogene locus, and the presence of human immunodeficiency virus (HIV) sequences in both LAS and B-NHL biopsies. Our data indicate that multiple clonal B cell expansions are present in a significant percentage of LAS (approximately 20%) and B-NHL (60%) biopsies. c-myc rearrangements/translocations are detectable in 9 of our 10 NHLs, but not in any of the LAS cases. However, only one of the B cell clones, identified by Ig gene rearrangements carries a c-myc gene rearrangement, suggesting that only one clone carries the genetic abnormality associated with malignant B cell lymphoma. Furthermore, the frequency of detection of c-myc rearrangements in AIDS-associated NHLs of both Burkitt and non-Burkitt type suggest that the biological alterations present in AIDS favor the development of lymphomas carrying activated c-myc oncogenes. Finally, our data show that HIV DNA sequences are not detectable in LAS nor in NHL B cell clones, suggesting that HIV does not play a direct role in NHL development. Taken together, these observations suggest a model of multistep lymphomagenesis in AIDS in which LAS would represent a predisposing condition to NHL. Immunosuppression and EBV infection present in LAS can favor the expansion of B cell clones, which in turn may increase the probability of occurrence of c-myc rearrangements leading to malignant transformation.
Gene correction in the evolution of the T cell receptor beta chain.
Authors: Jouvin-Marche E , Heller M , Rudikoff S
Published: June 2004

Mutational mechanisms operating at the T cell receptor beta chain locus have been examined by comparison of the CT beta 1 and CT beta 2 gene sequences from Mus pahari, believed to be the oldest living species in the genus Mus, with those of inbred mice. Results indicate that a gene correction event independent of that suggested to have occurred in inbred mice has homogenized the M. pahari CT beta exon 1 sequences, minimizing diversity in this region of the molecule. These observations suggest that correction events such as gene conversion may occur frequently, even in pauci-gene families with as few as two members, and therefore play a significant role in gene diversification or homogenization of small as well as large gene families.
Pancreatic islet cell surface glycoproteins containing Gal beta 1-4GlcNAc-R identified by a cytotoxic monoclonal autoantibody.
Authors: Uchigata Y , Spitalnik S L , Tachiwaki O , Salata K F , Notkins A L
Published: June 2004

To investigate the autoimmune pathogenesis of spontaneously occurring diabetes mellitus in BB rats, spleen cells of newly diagnosed diabetic BB rats were fused with mouse myeloma cells. Hybridoma supernatants were screened for antibodies by indirect immunofluorescence and by 51Cr-release assays using the RINm5F rat insulinoma cell line. One clone, E5C2, produced an IgM kappa antibody that was cytotoxic for RINm5F cells, but not for other rat cell lines nor for primary rat islet cells. However, treatment of primary rat islet cells with neuraminidase exposed surface antigens and rendered the cells susceptible to complement-mediated lysis by antibody E5C2. Using immunostaining of glycolipids separated by thin-layer chromatography, hapten inhibition assays with defined carbohydrates, and Western blots, the antigens recognized by E5C2 on RINm5F cells were identified as glycoproteins with molecular weights of 60,000 and 68,000. The antibody recognizes a carbohydrate antigen containing the sequence Gal beta 1-4GlcNAc-R, which on RINm5F cells is predominantly hidden by covalently bound sialic acid. These studies raise the possibility that hidden antigenic determinants on islet cells exposed by a variety of means may be the target of autoimmune attack.