bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of the optimal human cell lines for development of human hybridomas.
Authors: Abrams P G , Knost J A , Clarke G , Wilburn S , Oldham R K , Foon K A
Published: December 2022

Six human cell lines were compared with each other and with murine myeloma NS-1 as to their sensitivity to HAT medium and their ability to form hybrids with human lymphocytes, secret monoclonal immunoglobulin, clone, and maintain detectable levels of monoclonal immunoglobulin secretion for a period of time after fusion. Fusion efficiencies varied from 0 to 50%, and the incidence of immunoglobulin secretion ranged between 1 and 78% of the hybrids. Immunoglobulin secretion of cloned hybrids varied from 0.8 to 1.6 micrograms/ml/10(6) cells among the human-human hybrids and was 2.4 micrograms/ml/10(6) cells by the human-mouse hybrid. Among the lines tested, UC729-6 and HF2 appeared optimal for pursuing further studies with human-human hybridomas. In addition, although only a small percentage of hybrids were produced with HMy2, a very high percentage secreted immunoglobulin, so that this line also warrants further investigation to improve the efficiency of hybrid formation. Implications for specific monoclonal antibody production and for therapy of leukemias and lymphomas by anti-idiotype antibodies are discussed.
Fine specificity of the in vitro antibody response to influenza virus by human blood lymphocytes.
Authors: Mitchell D M , Callard R E
Published: December 2022

The fine specificity of anti-influenza antibody produced in vitro by human PBM stimulated with different strains of influenza virus was examined by competition binding in solid phase enzyme immunoassay. Most of the antibody produced in vitro is directed to strain-specific or cross-reactive determinants on the hemagglutinin molecule. The extent of cross-reactivity is dependent on the strain of virus used to stimulate PBM as well as the individual tested and presumably on his previous exposure to influenza viruses. PBM from some individuals produced antibody that bound to the stimulating strain of influenza virus but not to other strains of the same subtype. In other individuals, antibody was produced in vitro that cross-reacted with all viruses in the same subtype (e.g., H3N2; A/X31, A/X47, and A/Texas) but did not bind to other (H2N1 or H1N1) subtypes, and in a few individuals, extensive cross-reaction between subtypes was seen. The presence of antibody to hemagglutinin in these culture supernatants was confirmed by competition binding to highly purified hemagglutinin. This in vitro culture system allows the immunologic memory of individuals to a wide range of stimulating virus strains to be examined simultaneously in terms of specificity of the antibody response by human PBM to influenza virus after natural infection or immunization.
Role of macrophage-myelin basic protein interaction in the induction of experimental allergic encephalomyelitis in Lewis rats.
Authors: Carbone A M , Ovadia H , Paterson P Y
Published: December 2022

Stimulated peritoneal exudate cells (PEC) containing activated macrophages (M phi) of Lewis (Le) rats were exposed for 1 hr in vivo or in vitro to radioiodinated soluble myelin basic protein (MBP) or MBP incorporated into magnetic microspheres (MBP-microspheres). The uptake by M phi of the dose of microsphere-bound MBP averaged 6.2%, whereas the average uptake of soluble MBP was 0.17%. Naive rats were sensitized with M phi-associated MBP or M phi-associated MBP-microspheres via the hind footpads without the aid of conventional immunologic adjuvants. Draining lymph node cells (LNC) or spleen cells from sensitized rats were cultured for 3 days with guinea pig MBP (GPMBP) alone or in combination with concanavalin A (Con A), then injected i.v. into naive recipients. Clinical signs of experimental allergic encephalomyelitis (EAE) appeared 6 days after transfer of LNC or spleen cells, and typical CNS lesions were seen in recipients sacrificed 10 to 14 days after transfer. The challenge of MO-MBP-sensitized rats with MBP-CFA resulted in severe clinical signs of EAE marked by an accelerated onset of neurologic symptoms.
Alloreactive cloned T cell lines. VII. Comparison of the kinetics of IL 2 release stimulated by alloantigen or Con A.
Authors: Ely J M , Fitch F W
Published: December 2022

A cloned T amplifier cell, designated L2, was shown previously to release several lymphokine activities, including IL 2, following stimulation with either alloantigen or concanavalin A (Con A). However, the responses induced by the two stimuli differ significantly. When high numbers of L2 cells were stimulated with Con A, greater amounts of IL 2 were released whereas stimulation of high numbers of L2 cells with alloantigen resulted in the release of less than optimal levels of IL 2. IL 2 levels as high as 1500 units/ml were reached with Con A. When stimulated with alloantigen, the release of L2 cells was followed by proliferation. When stimulated with Con A, the cells did not proliferate. The inhibitory effect was related to the length of exposure of L2 cells to the lectin and could be avoided by removing the excess Con A from cultures 3-6 hours after stimulation. Thus, a brief exposure of L2 cells to Con A was sufficient to cause the release of high levels of lymphokine activities and permit the L2 cells to proliferate in a pattern similar to that after stimulation with alloantigen. These results are consistent with the hypothesis that the lectin, Con A, acts as a mitogen for cloned murine amplifier T cells only indirectly by triggering the release of growth factors which then promote cell proliferation.
Structural identity of the TL antigen homologues derived from strain 2 and strain 13 guinea pigs.
Authors: Surratt R S , Abruzzini L N , Zacheis M P , Cigen R , Schwartz B D
Published: December 2022

Strain 2 and strain 13 guinea pig thymocytes have been shown to bear a molecule that by several criteria appears to be a homologue of the murine TL antigen. The existence of a TL polymorphism in the mouse system as evidenced by TL- strains and various TL phenotypes in TL+ strains prompted a study to determine if a similar polymorphism could be demonstrated in the guinea pig system. By using two-dimensional gel electrophoresis, the thymocytes of a third inbred strain, DHCBA, were shown to bear a TL antigen, and the TL antigens of strains 2 and DHCBA were shown to give identical patterns of spots. A biochemical comparison of the strain 2 and strain 13 TL antigen heavy chains by tryptic and chymotryptic peptide mapping demonstrated that these molecules have identical peptides. Thus, no polymorphism could be demonstrated within the guinea pig TL system for the three inbred strains studied. Comparative tryptic peptide mapping of the guinea pig TL and class I B.1+S antigens demonstrated 43% homology, significantly higher than that reported for murine H-2 and TL antigens. These results provide suggestive evidence that the gene duplication giving rise to the genes determining the class I and TL antigens may have occurred more recently in the guinea pig than in the mouse.
The presence of NK alloantigens on cloned cytotoxic T lymphocytes.
Authors: Brooks C G , Burton R C , Pollack S B , Henney C S
Published: December 2022

A panel of sera raised against NK-1.1 and NK-2.1 alloantigens was tested for reactivity against a panel of cloned antigen-dependent CTL lines. By using indirect immunofluorescence and flow cytofluorimetry, weak, but clear and consistent, reactivity was found on all CTL. Concordant with the genetics of NK alloantigens, C57BL/6-derived clones were reactive with anti-NK-1.1 and anti-NK-2.1 sera, whereas CBA-derived clones were reactive with anti-NK-2.1 sera but not with anti-NK-1.1 sera. Cloned CTL lines were also able to partially and specifically absorb the antibodies from NK alloantiserum that reacted with splenic NK cells. These results indicate that cloned CTL lines express at least some of the NK alloantigen determinants present on splenic NK cells and have important implications regarding the relationship of CTL and NK cells.
Role of polymorphonuclear cells in Chagas' disease. I. Uptake and mechanisms of destruction of intracellular (amastigote) forms of Trypanosoma cruzi by human neutrophils.
Authors: Villalta F , Kierszenbaum F
Published: December 2022

The ability of human polymorphonuclear cells (PMN) to take up and destroy intracellular forms of Trypanosoma cruzi (AMA) was investigated as a part of our efforts to elucidate the mechanisms of clearing of these parasites from infected tissues. PMN were found to take up AMA and destroyed parasites were seen after 30 min of cell-parasite interaction. Under our experimental conditions, the rate of uptake of AMA by PMN was maximal during the first 30 min of interaction. AMA were found to be located and destroyed inside the phagolysosomal vacuoles of PMN. The parasite was never found outside these vacuoles despite electron microscopic examination of numerous preparations derived from several experiments. Intracellular destruction of AMA by PMN was visible by electron microscopy and could be monitored by measuring the release of 3H-labeled substances by PMN that had ingested radiolabeled AMA. PMN incubated after removal of unbound parasites destroyed over 90% of the ingested organisms within 3 hr and close to 99% after 12 hr. In cellfree systems, 44% of the AMA were destroyed in the presence of 10(-4) M H2O2 and all of the parasites died at 10(-3) M. Addition of lactoperoxidase and iodide resulted in 100% killing at 10(-5) M H2O2. These mechanisms appeared to be involved in the lysis of AMA by PMN since both H2O2 and peroxidase activity were demonstrated to be present in PMN vacuoles containing the parasite. Addition of NaN3, KCN (inhibitors of myeloperoxidase activity) or catalase (to decompose H2O2) caused a marked reduction in the extent of AMA killing by PMN. Xanthine oxidase was toxic for the AMA in the presence of acetaldehyde. This microbicidal activity was inhibited by catalase but not by heat-inactivated catalase or by reagents that scavenge the intermediate products of reduction of molecular oxygen, O - X 2, X OH, and 1O2. These results suggest that PMN have the potential of clearing AMA liberated in infected chagasic tissues and that parasite killing within the phagolysosomal vacuoles is mediated by myeloperoxidase activity and H2O2.
Genetic polymorphism of human C4-binding protein.
Authors: de Cordoba S R , Ferreira A , Nussenzweig V , Rubinstein P
Published: December 2022

Two different forms of human C4-bp, C4-bp A and C4-bp B, have been identified by isoelectric focusing (IEF) of neuraminidase-treated EDTA-plasma samples. Family studies demonstrate Mendelian segregation of these forms, indicating that they are under gentic control. This conclusion is supported by IEF analysis of the two variants purified by affinity chromatography. Under completely denaturing conditions, C4-bp B was found to be composed of two subunits that focused at different pH, whereas C4-bp A contains only the more basic one. These results suggest that a single autosomal locus with at least two codominant alleles coding for the subunits controls the IEF variation of C4-bp in humans. The allele designated C4BP*1 codes for a subunit that, after neuraminidase treatment, focuses at pH = 6.65. The allele C4BP*2 codes for a different subunit that focuses at pH = 6.60. The C4-bp A phenotype corresponds to the genotype C4BP*1,C4BP*1 and the phenotype C4-bp B to the genotype C4BP*1,C4BP*2. The phenotype corresponding to the C4BP*2,C4BP*2 homozygous genotype has not been encountered thus far. Initial linkage data indicate that the C4BP locus is not closely linked to either the HLA or to the C3 loci.
Recognition of influenza-infected cells by cytolytic T lymphocyte clones: determinant selection by class I restriction elements.
Authors: Vitiello A , Sherman L A
Published: December 2022

The fine specificity of virus recognition by influenza A/PR8/34(H1N1)-specific cytolytic T lymphocyte (CTL) clones was analyzed with the use of a panel of syngeneic target cells infected with five heterologous influenza A strain viruses. Forty-five H-2 D-end-restricted CTL clones from B10.A(5R) responders (Dd,Ld) demonstrated 14 different patterns of recognition. Many of these clonotypes were able to distinguish between closely related viruses of the same subtype. Such discriminatory capacity, however, was often accompanied by cross-reactivity against a distantly related viral subtype. This supports the contention that virus-specific CTL see different structures than do virus-specific antibodies. A similar analysis of the fine specificity of 60 Db-restricted clones from C57BL/6 responders was performed. The vast majority of this response was composed of clonotypes not observed in the B10.A(5R) response. In addition, the hierarchy of relatedness between the virus strain used for immunization and the various heterologous viruses was different in C57BL/6 and B10.A(5R). In contrast, the D-end-restricted response of Balb/c (Dd,Ld) demonstrated clonotypes similar to those found in B10.A(5R). These data suggest that determinant recognition in an anti-viral CTL response is a function of the H-2 restricting elements, and this is discussed in the context of determinant selection by class I molecules.
A comparison of the neonatal tolerance-inducing capacities of H-2 class I and class II antigens.
Authors: McCarthy S A , Bach F H
Published: December 2022

We have investigated the abilities of murine major histocompatibility complex-encoded antigens to induce in vitro hyporeactivity of T lymphocytes when these antigens are injected neonatally. Class I molecules, presented on F1 donor cells having an H-2 K or D region difference from recipients, can readily induce tolerogen-specific cytotoxic T cell hyporeactivity; as few as 1 X 10(6) neonatally injected donor cells suffice. In contrast, class II molecules, presented on F1 donor cells having an H-2 I region difference from recipients, can induce tolerogen-specific helper T cell hyporeactivity only when at least 1 X 10(7) neonatally injected donor cells are used, and then only in some of these recipients. Results from another in vitro assay system, taken in conjunction with these data, indicate that the molecular class of the tolerizing disparity, rather than the effector function of the responding cell type assayed, may be the most important factor in controlling the ease with which neonatally induced alloantigen tolerance can be achieved. In each type of tolerance described here, the hyporeactivity seen is antigen specific, in its induction and its expression; the implications of this fact for considerations of possible mechanisms of tolerance maintenance are discussed.
Clonal abortion of bone marrow T cell precursors: T cells acquire specific antigen reactivity prethymically.
Authors: Chervenak R , Cohen J J , Miller S D
Published: December 2022

Lethally irradiated (900 R) mice were reconstituted with bone marrow cells from syngeneic donors that had been tolerized 2 to 3 wk earlier to either DNP or TNP compounds. Five weeks after reconstitution, these animals were tested for their ability to mount a delayed hypersensitivity (DH) response to the tolerizing haptens. Recipient mice were specifically tolerant to the hapten that was used to induce tolerance in the marrow donor. Mixing experiments in which mice were reconstituted with marrow from DNP-tolerant and TNP-tolerant donors showed no indication of active suppression or effective antigen carry-over in this system. This observation held true even in experiments in which mice were reconstituted with a mixture of marrow from tolerant and normal donors at a ratio of 5:1. Thus the reduced responsiveness in recipient mice seemed to be due to the functional elimination of hapten-responsive T cell precursor (pre-T) clones. Recipient unresponsiveness was also shown to be MHC restricted. Maintenance of unresponsiveness appeared to be due to the restricted access of regenerating pre-T cell clones to the maturational influence of the recipient's thymus.
Differentiation of B lineage cells from liver of neonatal mice: generation of immunoglobulin isotype diversity in vitro.
Authors: Calvert J E , Kim M F , Gathings W E , Cooper M D
Published: December 2022

The development and differentiation of B cells expressing different immunoglobulin (Ig) isotypes was studied in cultures of murine neonatal liver cells. Before culture, 5 to 15% of the liver cells were mu + pre-B cells; 1 to 3% had surface IgM and less than 0.1% had slgG. During 4 days in culture the number of pre-B cells declined, whereas the number of IgM B cells increased greater than 20-fold; IgG B cells also increased in number. Of the four subclasses, IgG3+ and IgG2b+ cells predominated, each representing 3 to 10% of the total B cells at day 4. IgG1+ and IgG2a+ cells were present in lower numbers, representing 1 to 5% and 0.3 to 2.5% of B cells, respectively. Most IgG+ cells also expressed sIgM. Only a minority (less than 10%) of the sIgM+ cells were sIgD+, and most sIgG+ cells were sIgD-. Few T cells were present in these cultures (less than 0.5% in newborn liver), and sIgG+ cells were generated in normal frequencies in cultures of cells from nude mice. The numbers of B cells expressing each IgG subclass were similar in cultures from athymic nu/nu mice, nu/+ heterozygous littermates, and normal BALB/c mice. Plasmablasts and plasma cells appeared over a 14-day culture interval, and these expressed cytoplasmic IgM, IgG3, IgG1, IgG2b, IgG2a, and IgA. Measurable amounts of the first four isotypes were detected in the culture supernatants by radioimmunoassay. These results indicate that neonatal B cells can undergo isotype switching in the absence of T cell help, and that the expression of sIgD may not be a prerequisite for cells to switch Ig isotypes.
Dissociation between macrophage tumoricidal capacity and suppressive activity: analysis with macrophage-defective mouse strains.
Authors: Boraschi D , Pasqualetto E , Ghezzi P , Salmona M , Bartalini M , Barbarulli G , Censini S , Soldateschi D , Tagliabue A
Published: December 2022

Macrophages (M phi diameter) from three mouse strains with genetically distinct M phi diameter deficits (C3H/HeJ, A/J, and P/J) were unable to develop high cytolytic and cytotoxic activity against tumor cells in vitro when exposed to agents (MAF and IFN-beta) that strongly increased the tumoricidal capacity of M phi diameter from nondefective C3H/HeN mice. Nevertheless, the tumoricidal deficits of M phi diameter from the defective strains did not affect their suppressive capacity on Con A-induced lymphoproliferation, nor their ability to react to IFN-beta by decreasing suppressive activity. In fact, natural suppressive activity and IFN-beta-induced changes in the suppression of M phi diameter from C3H/HeJ, A/J, and P/J mice were highly comparable to those of C3H/HeN M phi diameter, thus stressing the dissociation between the mechanisms governing M phi diameter suppression and M phi diameter tumoricidal activity. Analysis of the modulation by MAF and IFN-beta of M phi diameter ability to release the oxygen metabolites O2- and H2O2, molecules possibly involved in the effector mechanism of both M phi diameter cytotoxicity and suppression, revealed a close correlation with the patterns of suppressive activity in both nondefective and defective strains. In contrast, no correlation between the production of oxygen-reactive species and M phi diameter tumoricidal activity was observed. The ability of MAF- and IFN-beta-treated M phi diameter to produce PGE, a molecule of major importance in M phi diameter-mediated suppression and possibly involved also in the regulation of M phi diameter tumoricidal activity, again paralleled M phi diameter suppressive capacity. Thus, the mechanisms controlling M phi diameter antitumor activity appeared to be clearly distinct from those involved in M phi diameter suppression.
Transport of immune complexes from the subcapsular sinus to lymph node follicles on the surface of nonphagocytic cells, including cells with dendritic morphology.
Authors: Szakal A K , Holmes K L , Tew J G
Published: December 2022

The objective of the present study was to investigate the mechanism of antigen migration from the site of initial localization in the lymph node subcapsular sinus (SS) to regions of follicular retention in the cortex. The migration of horseradish peroxidase (HRP), used as a histochemically identifiable antigen, was followed by light and electron microscopy in C3H mouse popliteal lymph nodes obtained 1, 5, 15, and 30 min, and 5 and 24 hr after hindfoot pad injection of HRP. The observations showed that as early as 1 min after HRP injection, localization of antigen occurred at distinct sites in the SS and subjacent areas of the cortex on the afferent side. At these sites, between 1 min and 24 hr, the antigen formed light microscopically identifiable trails, which reached progressively deeper into the cortex with time toward individual follicular regions. By 24 hr this apparent migration of antigen was complete, and HRP was localized in follicles. This migration pattern did not occur on the efferent sides of lymph nodes, and it was dependent on the systemic presence of specific antibodies since it was observable only in passively immunized but not in nonimmune mice. Temporary retention of antigen by typical macrophages was also observed in the SS on the efferent side. This was minimal in nonimmune mice and was significantly enhanced in passively immunized mice. Electron microscopy indicated that the apparent migration of immune complexes was mediated by a group of cells observed in the migration path that had immune complexes sequestered on their surface or in plasma membrane infoldings. These antigen transporting cells (ATC) were relatively large nonphagocytic cells, with lobated or irregular euchromatic nuclei and cell processes of various complexity. ATC observed in or near the SS appeared to be less differentiated, were monocyte-like, and resembled non-Birbeck granule-containing Langerhans cell precursors or veiled cells. Others, located deeper in the cortex, appeared more differentiated, interdigitated with antigen-retaining dendritic cells, and shared morphologic characteristics with follicular dendritic cells (FDC). The results support the concepts that immune complexes are trapped in the SS and are transported by a group of non-phagocytic cells, other than lymphocytes, to follicular regions. The mechanism of transport may involve the migration of ATC with a concomitant maturation into FDC, or by a mechanism of ATC to FDC transport utilizing dendritic cell processes and membrane fluidity, or by a combination of the two mechanisms.
Blockade of NK cell lysis is a property of monoclonal antibodies that bind to distinct regions of T-200.
Authors: Newman W , Fast L D , Rose L M
Published: December 2022

The previously described NK inhibitory monoclonal antibody 13.1 is shown to immunoprecipitate a series of high m.w. glycoproteins homologous with the murine T-200/Ly-5 molecules. Not all antibodies to the human T-200 molecule, however, have an inhibitory effect on NK cell function. A comparison is made between two noninhibitory anti-T-200 antibodies, 13.5 and 13.6, and two inhibitory anti-T-200 antibodies, 13.1 and 13.3. All antibodies are of the IgG1 subclass. Sequential immunoprecipitation experiments show that these antibodies react with the same set of molecules. The differences in NK-blocking activity could not be explained by the amount of antibody bound per cell in NK-enriched populations, nor by the avidity with which they bound. It is shown by competitive radiobinding assays that the 13.1 and 13.3 antibodies define a region, termed region A, distinct from that defined by the nonblocking antibodies 13.5 and 13.6, termed region B. Region B is shown to reside between the membrane and region A. These findings show that the inhibition of NK lysis by anti-T-200 antibodies is a function of the site on that molecule to which these antibodies bind. This may also explain the ability of antibodies to the A region of T-200 to block selectively the lysis of myeloid and erythroid tumor targets, with no effect on the lysis of T lymphoma targets.
Delineation of suppressor and helper activity within the OKT4-defined T lymphocyte subset in human newborns.
Authors: Jacoby D R , Oldstone M B
Published: December 2022

Lymphocytes taken from the cord blood of newborns have active suppressor activity. Using in vitro PWM-stimulated cocultures, unfractionated T cells from newborns potently suppressed the expected immunoglobulin G (IgG) synthesis of their mothers' peripheral blood lymphocytes (PBL). Using positive and negative selection techniques, we characterized the active suppressor cell as expressing the OKT4+T8- phenotype. This cord blood lymphocyte subset suppressed maternal IgG synthesis after depletion of maternal suppressor cells, implicating the ability of newborn T cells to suppress directly rather than by inducing adult suppressor activity. Sublethal amounts (1500 rad) of gamma-irradiation fully abrogated the suppressor activity of cord blood T lymphocytes. Radioresistant cord T cells provided T cell help. Irradiation of cord OKT4+ and OKT8+ populations and their subsequent culture with maternal B cells determined that helper activity was a radioresistant subpopulation of the OKT4+ subset. These results indicate significant differences in the functional properties of T cell subsets from adults and newborns. Population studies determined that cord blood lymphocytes had a greater proportion of OKT4+ cells and lower proportion of OKT8+ cells than PBL from unrelated adults. The mothers tested had similar proportions of OKT4+ cells as their babies, and these levels are significantly higher than those of unrelated adults.
Characterization of a monoclonal antibody directed to a T cell suppressor factor.
Authors: Maier T , Stammers A T , Levy J G
Published: December 2022

A monoclonal antibody raised by fusion of immune BALB/c splenocytes with NS1 cells is described. BALB/c mice were immunized with a T suppressor factor (TsF) raised in DBA/2 mice with specificity for the P815 tumor. The TsF had been purified by affinity chromatography before its use as an immunogen. The monoclonal antibody (B16G) was shown to affect the course of P815 growth in DBA/2 mice if administered i.v. on days -2 to 0 before tumor cell inoculation. Mice treated with B16G demonstrated slower tumor development and growth than controls, and a small number of animals (about 10%) did not develop tumors; all controls did. It was also shown that B16G did not exhibit total specificity for the P815 tumor in that it had similar effects on the growth of an unrelated myosarcoma (M-1) of DBA/2 mice. The general immunopotentiating effect of the B16G monoclonal was demonstrated by the fact that spleen cells of DBA/2 mice that had received B16G showed significantly higher MLC than did equivalent controls. When spleen cells of DBA/2 mice were depleted of B16G-reactive cells by panning in vitro, it was also found that cells so treated gave rise to elevated MLC reactions in comparison to appropriate controls. When an immunoadsorbent was prepared with B16G and cell lysates from splenocytes of immunosuppressed mice were passed over it, the immunosuppressive properties of the lysate in MLC were eliminated. The conclusion that the B16G recognizes a marker common to a group of regulatory T cells in DBA/2 mice is discussed.
Ia antigen: a murine B lymphocyte receptor for transformed cell induction of interferon-alpha/beta.
Authors: Hughes T K , Blalock J E
Published: December 2022

A receptor on the surface of nonsensitized mouse spleen cells that recognizes a glycoprotein from transformed mouse L-929 cells is described. The interaction of the receptor and glycoprotein inducer results in the production of MoIFN alpha/beta. An assay was developed to assess certain biologic and physicochemical characteristics of the receptor. The receptor and glycoprotein inducer bound in a concentration-dependent manner, which tends to indicate a direct interaction between the two. The receptor was not ubiquitous; spleen cells but not normal mouse embryo cells appeared to be the source. It was specific for MoIFN alpha/beta inducers from transformed cells, but not from other MoIFN alpha/beta or gamma inducers such as NDV, LPS, PWM, or SEA. The receptor appeared to be a cell surface protein in that its activity was abolished by trypsinization of whole spleen cells. Previous studies indicated that the receptor was probably located on B cells. Gel filtration indicated that the receptor had a m.w. of 30,000 to 60,000. Because the receptor appeared to be: 1) B lymphocyte associated, 2) a surface protein, and 3) 30,000 to 60,000 daltons, a similarity to Ia antigen was suggested. This possibility was confirmed by showing binding of the receptor to an anti-IaK antibody-Sepharose affinity column. PAGE analysis of the affinity-purified receptor revealed a single protein band with a m.w. of approximately 60,000. ELISA of the above gel slices with anti-Ia antibody further confirmed the specificity of the column. A physical association of the receptor and inducer was demonstrated by showing binding of the glycoprotein inducer to a receptor (Ia antigen)-Sepharose affinity column. Furthermore, the receptor (Ia antigen) was highly purified by a glycoprotein inducer-Sepharose affinity column.
Cell surface antigen expression in newborn cord blood lymphocytes infected with HTLV.
Authors: Mann D L , Popovic M , Murray C , Neuland C , Strong D M , Sarin P , Gallo R C , Blattner W A
Published: December 2022

Human T cell lymphocyte lines, established from lymphoid tissues from patients with adult T cell malignancies infected with the human T cell lymphoma virus (HTLV), were used in co-culture experiments to infect newborn cord blood lymphocytes (CBL). The infected and non-infected CBL cell lines were typed for HLA alloantigen determinants and tested for cell surface antigens using selected monoclonal antibodies. Infected cord blood lymphocytes showed inappropriate expression of alloantigenic determinants of the HLA-A and -B alleles. The monoclonal antibody 4D12, detecting an antigen common to the HLA-B5 cross-reactive group, was reactive with all infected cultures; this determinant appeared de novo in CBL cells lacking B5 cross-reactive group antigens in the uninfected state, and it increased in density in the infected cultures where the HLA-B5 cross-reactive alloantigens were present in uninfected CBL. HLA-DR was expressed in low levels or not detected on non-infected cultured cord blood lymphocytes and was present on all infected cells. OKT4 positive cells predominated in infected cultures, whereas OKT8 positive cells decreased in number or were absent. The TCGF receptor also increased both in density and in percent positive cells in all infected cell lines. The results suggest that HTLV may be tropic for a subset of T cells expressing mature T cell markers and that viral infections directly affect expression of cell surface antigens controlled by the human major histocompatibility complex (MHC).
Extensive polymorphism surrounding the murine Ia A beta chain gene.
Authors: Robinson R R , Germain R N , McKean D J , Mescher M , Seidman J G
Published: December 2022

A segment of the murine immune response-associated (Ia) antigen A beta chain mRNA has been cloned, and this cDNA clone has been used to examine the organization of the genes encoding these highly polymorphic cell surface proteins. To isolate this clone, pIA beta-1, we screened 5000 cDNA clones by a filter hybridization-selection assay using a rabbit heteroantiserum to identify the A beta chain produced in in vitro translation reactions. This clone corresponds to a segment of the mRNA encoding the beta chain of the murine I-A antigen. The 464 bp nucleotide sequence of the insert is consistent with a cDNA clone encoding the carboxyl end of the murine A beta chain. Comparison of this nucleotide sequence to a human Ia beta chain-derived cDNA clone suggests that the two clones could encode proteins that are about 90% homologous in this region. Southern blot analysis using pIA beta-1 as a probe to investigate the structure of the A beta chain gene in inbred strains of mice allows two conclusions. First, there is only one A beta chain gene homologous to this cDNA clone in each haploid mouse genome. Second, the restriction fragments encoding this gene are highly polymorphic. We postulate that the mechanism which generates polymorphic variation of the A beta chain may be involved in generating the restriction site polymorphism within or near the A beta chain gene.
Expression of the major histocompatibility antigens HLA-A2 and HLA-B7 by DNA-mediated gene transfer.
Authors: Bernabeu C , Finlay D , van de Rijn M , Maziarz R T , Biro P A , Spits H , de Vries J , Terhorst C P
Published: December 2022

Genes coding for the heavy chain of the class I antigens HLA-A2 or HLA-B7 of the human major histocompatibility complex have been introduced into mouse LtK- cells by cotransfection with the herpes simplex virus thymidine kinase gene. HAT-resistant colonies were isolated expressing either HLA-A2 or HLA-B7 as monitored by indirect immunofluorescence. Immunoprecipitation analysis of both antigens by either sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) or isoelectric focusing (IEF) showed that they were identical to the HLA-A2 and HLA-B7 expressed in the human lymphoblastoid cell line JY (homozygous HLA-A2, HLA-B7). However, human cytotoxic T lymphocytes (CTL) generated against JY and CTL clones specific for HLA-A2 or HLA-B7 were unable to recognize the transfectants as targets. These results indicate that the human HLA-A2 (or B7) complexed with the murine beta 2-microglobulin could be an inappropriate target structure for the CTL. However, because the transfectants are not killed by human CTL even in the presence of lectins, it is suggested that other molecules that are not able to overcome the human-mouse species barrier may be involved in the killing mechanism.
In vitro interaction with antigen suppresses the differentiation of chronic lymphocytic leukemia cells secreting monoclonal anti-sheep red blood cell antibody.
Authors: Fiorilli M , Misiti J , Pandolfi F , Semenzato G , Waldmann T A
Published: December 2022

Leukemic B cells from a patient with chronic lymphocytic leukemia had membrane-bound IgM that reacted against a sheep red blood cell (SRBC) antigen. A small proportion of these cells was able to differentiate into anti-SRBC hemolytic plaque-forming cells when cultured in vitro in the absence of polyclonal stimulators. The addition of pokeweed mitogen or of x-irradiated allogeneic T cells further enhanced their differentiation. The addition of antigen (SRBC) to unstimulated cultures of the patient's mononuclear cells suppressed the anti-SRBC antibody production. Marked suppression was induced by concentrations of SRBC that were found to stimulate anti-SRBC antibody production optimally by normal peripheral blood mononuclear cells. Two lines of evidence suggest this inhibition was not due to the activation of suppressor cells. First, depletion of T cells with the phenotype reported to be associated with suppressor cells, namely OKT8+ cells, did not prevent suppression. Secondly, the patient's mononuclear cells pulsed with SRBC did not suppress anti-SRBC antibody production by untreated autologous cells in co-culture. These findings suggest that leukemic cells were inhibited by the direct interaction with antigen. This suppression might be the result of intrinsic abnormalities of leukemic B cells. Alternatively, it could be the reflection of a tolerogenic response to antigen stimulation displayed by the patient's leukemic cells, which have a surface phenotype, IgM+D-, that is comparable to that of immature normal B cells.
Response against single minor histocompatibility antigens. I. Functional and immunogenetic analysis of cloned cytolytic T cells.
Authors: Roopenian D C , Widmer M B , Orosz C G , Bach F H
Published: December 2022

A clonal approach was used to investigate the cellular basis of a T cell response to single minor histocompatibility antigens (miHA). This analysis was performed by functional and immunogenetic characterization of a large number of clones derived from short-term mixed leukocyte culture (MLC) populations generated against the miHA, H-1.3. Forty-nine clones isolated from such MLC were specifically cytolytic for H-1.3-bearing, H-2Db-compatible target cells. Thirty-seven of the 49 cytolytic clones were driven to proliferate when stimulated by spleen cells bearing the H-1.3 alloantigen in the absence of added T cell-derived growth factor(s) (GF). The remaining 12 clones proliferated only when GF was added. A strong positive correlation was observed between antigen-induced proliferation and the production of interleukin 2 (IL 2) activity. A similar correlation was observed when comparing the ability of both antigen and concanavalin A to induce IL 2 activity from the clones. These data suggest that i) antigen-driven or helper T cell-independent cytolytic T cells (HITc) are frequent components of an MLC response to a single miHA, and ii) the ability of HITc to undergo antigen-driven proliferation is related to their ability to produce antigen-induced GF.
Population dynamics of T lymphocytes. Renewal rate and expansion in the peripheral lymphoid organs.
Authors: Rocha B , Freitas A A , Coutinho A A
Published: December 2022

This study investigated the renewal patterns of T lymphocytes in mice. T cell subpopulations in the thymus, bone marrow, spleen, and lymph nodes of normal, shamthymectomized, thymectomized, and splenectomized + thymectomized BALB/c or C57BL/6 mice were identified with monoclonal antibodies to Thy-1, Lyt-1, and Lyt-2 antigens at different times after the administration of hydroxyurea in a regimen shown to deplete cycling cells. As assessed in control experiments, hydroxyurea was not toxic to noncycling lymphocytes and it had no immediate effect on the numbers of mature peripheral T lymphocytes. The injection of hydroxyurea, however, was followed by a decline of T cell numbers to approximately 50% of initial values 24 to 76 hr later, demonstrating that 50% of peripheral T lymphocytes have a short lifespan and indicating the rapid renewal of T cells at the periphery. Furthermore, differential renewal rates were observed in T cell subpopulations defined both by differentiative Lyt phenotype and spleen or lymph node localization. These findings reveal that although the majority of peripheral T cells are not in cycle, they belong to a rapidly renewing population derived after a short transition time from their dividing precursors. The relative contribution of the thymus and of post-thymic expansion to the renewal of the peripheral T cell pool was also evaluated. The results demonstrate high renewal rates in the peripheral T cell compartment, indicate that post-thymic T cells are competent to undergo considerable expansion, and suggest homeostatic mechanisms that regulate the total numbers of peripheral T cells even in thymectomized individuals.
Suppression of humoral immune responses by synthetic C3a peptides.
Authors: Morgan E L , Weigle W O , Erickson B W , Fok K F , Hugli T E
Published: December 2022

Synthetic oligopeptides based on the COOH-terminal sequence of native human C3a were examined for the ability to suppress antigen-specific and polyclonal antibody responses. The synthetic peptides were found to qualitatively mimic the suppressive actions of human C3a, but proved to be less active on a molar basis. Comparison of the activity of the peptides with native C3a indicates that the most potent peptide is C3a 57-77 with C3a 65-77, C3a 70-77, C3a[Ala 71,72]70-77, and C3a 73-77 being less active, respectively. These results indicate that the region of the C3a molecule responsible for immunosuppression is located in the COOH region.
Dual contribution of embryonic ventral blood island and dorsal lateral plate mesoderm during ontogeny of hemopoietic cells in Xenopus laevis.
Authors: Kau C L , Turpen J B
Published: December 2022

The early embryonic development of hemopoietic cells in Xenopus laevis was examined. Either dorsal lateral plate (DLP) or ventral blood island (VBI) mesoderm was reciprocally transplanted between cytogenetically distinct (2N or 3N) stage 14 to 19 (neural fold) embryos. F-DNA content of circulating erythrocytes was assayed at stages 40, 41, 43, 45, and 49. The F-DNA content of cells in the thymus and mesonephros was assayed at stage 49. F-DNA values were used to distinguish between donor or host origin of hemopoietic cells in individual animals. The results demonstrated that DLP mesoderm gave rise to a population of stem cells that colonized the thymus and mesonephros, but not the blood. VBI mesoderm gave rise to a population of stem cells that colonized the blood and thymus, but not the mesonephros. These experiments show that there are two stem cell compartments in the amphibian embryo, separated in both space and time.
Human-human B cell hybridomas from in vitro stimulated lymphocytes of patients with common variable immunodeficiency.
Authors: Denis K A , Wall R , Saxon A
Published: December 2022

Human-human B cell hybridomas have been established from the peripheral blood lymphocytes of patients with common variable immunodeficiency (CVI) by fusion with an HGPRT-negative B lymphoblastoid cell line. IgM-secreting hybridomas were successfully obtained from CVI lymphocytes after stimulation for 5 days in vitro with a combination of PWM and Staphylococcus aureus strain Cowan I. Fusion of peripheral blood lymphocytes that were stimulated for 5 days in vitro with a single mitogen resulted in no viable hybrids from a total of 600 X 10(6) CVI lymphocytes. The combination of PWM and Cowan I did not induce appreciable Ig secretion from the CVI lymphocytes during the 5-day course, although it did so in normal lymphocytes. After the 5-day stimulation with this mitogen combination, however, a large percentage of the original number of peripheral blood cells were recovered, and these had a fusion frequency of approximately 1 to 2 per 10(6) with the B lymphoblastoid line. Fifteen cloned IgM-secreting hybridomas have been isolated from five different CVI patients. These hybridomas are tetraploid and have been stable in culture for 6 to 12 mo. All of the hybridoma lines that were examined contain a functionally rearranged IgM heavy chain gene from the B cell parent of the CVI patients. These human-human B cell hybridoma lines will enable a more thorough characterization of the B cell defects involved in CVI at the cellular and molecular levels.
In vitro stimulated peripheral blood lymphocytes from multiple sclerosis patients produce idiotypes of oligoclonal CSF IgG.
Authors: Nagelkerken L M , Out T A
Published: December 2022

Anti-idiotypic (anti-Id) antisera prepared against IgG from the cerebrospinal fluid of patients with multiple sclerosis were used to analyze culture supernatants of in vitro stimulated peripheral blood lymphocytes (PBL) from the patients. In the culture supernatants of pokeweed mitogen-stimulated PBL of four patients, idiotype-positive IgG was found. This finding provides additional evidence that the production of oligoclonal IgG in multiple sclerosis is not exclusively a feature of the central nervous system, but is also a systemic immunologic phenomenon.
Ontogeny of the MHC antigens on human trophoblast cells during the first trimester of pregnancy.
Authors: Montgomery B , Lala P K
Published: December 2022

The presence and the ontogeny of class I and class II major histocompatibility (MHC) antigens were investigated on human trophoblast cells in single cell suspensions of collagenase dispersed placentae during the first trimester of pregnancy by using a highly sensitive radioautographic approach. Cells were treated with monoclonal anti-HLA-A,B,C or anti-HLA-DR (or anti-human Ia) antibodies followed by 125I-labeled protein A, normal mouse serum, or medium alone used as negative controls, and monoclonal antibodies against trophoblast specific antigenic markers (anti-Trop 2, NDOG-1, and NDOG-2) used as positive controls for specificity of trophoblast labeling. Tissue controls were provided by Ficoll-paque-separated adult human peripheral blood lymphocytes (PBL), and placental lymphocytes were used as additional internal controls. Results revealed variable but specific labeling of cytotrophoblast cells for class I but not class II MHC antigens at all gestational stages during the first trimester. The incidence of HLA-A,B,C antigen-bearing cytotrophoblast cells in early gestational (5 to 8 wk) placentae was high (75 to 91%) in the minority, but was low to medium (35 to 66%) in placentae at later gestational intervals (9 to 12 wk). The initial antigen density on the labeled cytotrophoblast cells as reflected by the median silver grain counts per unit area was approximately 75% of that noted on adult PBL or placental lymphocytes at 5 to 7 wk. The density then dropped to 50% of the initial level by the eighth week of gestation with no further change up to 12 wk. Syncytiotrophoblast cells revealed no appreciable labeling for either antigen class. This could not be explained by antigen stripping due to the collagenase dispersion procedure; specific labeling was not detectable on the syncytiotrophoblast cell layer in situ in histologic sections after intact chorionic villi had been directly exposed to 125I-labeled monoclonal anti-class I antibody. These results are qualitatively similar to our findings in the mouse in revealing the presence of class I MHC antigens on a major population of trophoblast cells.
The release of platelet-activating factor from human endothelial cells in culture.
Authors: Camussi G , Aglietta M , Malavasi F , Tetta C , Piacibello W , Sanavio F , Bussolino F
Published: December 2022

The release of platelet-activating factor (PAF) from stimulated human endothelial cells (HEC) cultured from normal term, umbilical cord veins is described. HEC in primary cultures released PAF after challenge with A23187, rabbit anti-human factor VIII (RaHu/FVIII), angiotensin II, and vasopressin. HEC subcultures maintained the ability to release PAF in the presence of A23187 and RaHu/FVIII, whereas the release of PAF in response to angiotensin II and vasopressin was not constant and was reduced. Control cultured, smooth muscle cells derived from umbilical cord veins, previously depleted of endothelial cells, did not release PAF under the above-mentioned stimulation. Plastic-adherent or cultured monocytes released PAF with A23187, but not with RaHu/FVIII, angiotensin II, and vasopressin. The release of PAF from HEC in primary cultures required the presence of extracellular cations and the activation of membrane phospholipase A2. PAF release induced by A23187, RaHu/FVIII, angiotensin II, and vasopressin was unaffected by indomethacin, an inhibitor of cyclooxygenase, which, however, favored the release of PAF from HEC stimulated with thrombin, a stimulus that did not affect HEC in the absence of indomethacin. PGI2 inhibited PAF release from stimulated HEC. The relevance of an acetylation process in the biosynthesis of PAF and HEC was supported by the following evidence: 1) the increase in PAF yield in the presence of sodium acetate and, particularly, of acetyl-CoA; 2) the incorporation of [14C]acetate into PAF molecules; 3) the loss of radioactivity and of biologic activity after treatment with phospholipase A2. These results indicate that HEC in culture are able to release PAF and that metabolic pathways similar to those described for leukocytes are involved.