bluuebunny/crossref_metadata_2025 huggingface dataset:
Variant class II molecules from H-2 haplotypes in wild mouse populations: functional characteristics of closely related class II gene products.
Authors: Peck A B , Darby B , Wakeland E K
Published: December 2022

Independently derived haplotypes found in wild populations of mice often express class II molecules antigenically related to specific alleles of the A molecules defined in laboratory mice. Tryptic peptide fingerprint comparisons of these antigenically related molecules indicate that they have similar, or possibly identical, primary structures in the A alpha, A beta, or both subunits. By using the Ak and Ap families of independently derived, antigenically related A molecules, we examined the effect that minor structural variations in the A molecule have on allorecognition by T lymphocytes. Data obtained indicate that a) minor structural variations in the A molecule can effect, although not always, major functional changes in allorecognition, b) changes in allorecognition are always detected when the A beta subunit contains structural variations, but not necessarily when the A alpha subunit contains structural variations, and c) more than one site in the A molecule can be recognized by alloreactive T lymphocytes. These results can be interpreted as indicating that specific sites within the A molecule are critically involved in allorecognition and that structural variations must affect these sites to elicit major changes in allorecognition.
The site of action of N-alpha-tosyl-L-lysyl-chloromethyl-ketone (TLCK) on cloned cytotoxic T lymphocytes.
Authors: Pasternack M S , Sitkovsky M V , Eisen H N
Published: December 2022

N-alpha-tosyl-L-lysyl-chloromethyl-ketone (TLCK), an irreversible inhibitor of trypsin-like serine proteases, is a potent, nontoxic inhibitor of cytotoxic T lymphocyte (CTL) activity with half-maximal inhibition of an alloreactive CTL clone occurring at [TLCK] = 30 microM. We have utilized TLCK as an affinity probe for functionally important CTL surface molecules by raising rabbit antibodies specific for the tosyl group and employing them as immunoprecipitating reagents. When 125I-labeled cloned CTL were treated with TLCK, immunoprecipitation with rabbit anti-tosyl antibodies and analysis by polyacrylamide gel electrophoresis revealed a small number of TLCK-binding proteins. Prior alkylation of radiolabeled CTL with iodoacetamide inhibited TLCK binding only slightly, suggesting that TLCK binding did not occur via free sulfhydryl groups. Thymocytes and a second CTL clone both had very similar patterns of TLCK-binding proteins; in contrast the TLCK-binding proteins of B cells differed greatly. Sequential immunoprecipitation experiments identified the predominant CTL TLCK-binding protein as T200. Lymphocyte function-associated antigen-1 also reacted with TLCK but to a lesser extent. The inhibitory role of cell-surface bound TLCK (vs intracellular TLCK) was demonstrated by protection experiments using Concanavalin A, a reversible ligand of the CTL cell surface. These experiments suggest that T200 may be required for cytotoxic activity of CTL.
Cell receptors for the mammalian reovirus. II. Monoclonal anti-idiotypic antibody blocks viral binding to cells.
Authors: Kauffman R S , Noseworthy J H , Nepom J T , Finberg R , Fields B N , Greene M I
Published: December 2022

A monoclonal anti-idiotypic antibody directed against an idiotypic determinant on a monoclonal anti-reovirus type 3 hemagglutinin antibody with viral neutralization activity is capable of binding to the surface of lymphoid cells (BW5147, R.1.1, and R1.E) and of inhibiting viral binding to cell surface receptors. The inhibition of viral binding was specific for the anti-idiotype antibody; viral binding was not inhibited by antibodies bound to the H-2k and Thy-1.2 antigens on the surface. Viral binding to idiotype-negative cells (P-815, EL-4) was not inhibited by the anti-idiotypic antibody, although these cells are susceptible to type 3 reovirus infection. These data suggest that there are at least two structural classes of type 3 reovirus receptors on murine cells. It is probable that anti-idiotypic antibodies of this type will be useful in studying the structure and regulation of viral receptors on cell surfaces and for the purification of these receptors, and may provide a way to block viral infection.
Monoclonal antibodies against surface determinants on gametes of Plasmodium gallinaceum block transmission of malaria parasites to mosquitoes.
Authors: Kaushal D C , Carter R , Rener J , Grotendorst C A , Miller L H , Howard R J
Published: December 2022

Monoclonal antibodies (MAb) against gametes of the chicken malaria Plasmodium gallinaceum have been derived. All reacted with the surface of extracellular gametes of the parasite in immunofluorescent antibody reactions and all agglutinated both male and female gametes. In the absence of active complement one mu isotype MAb, la 1-D5, mediated at least 95% suppression of infectivity of the parasites to Aedes aegypti mosquitoes. Individually, MAb of the gamma 1 or gamma 2a isotypes mediated only slight suppression in the absence of active complement. Certain combinations of these MAb, however, suppressed parasite infectivity by 90 to 95%. Suppression of infectivity by the MAb was shown to be mainly due to their effects on the events leading up to or including fertilization. Certain gamma 2a isotype MAb, which otherwise mediated minimal or no suppressive effect, completely abolished infectivity of the parasites if complement was present. No target antigen could be identified by immunoprecipitation of Triton X-100 extracts of surface radioiodinated zygotes or gametes of P. gallinaceum for the mu isotype MAb. All gamma isotype MAb precipitated the same three proteins of 240,000, 56,000, and 54,000 daltons under reducing conditions on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, from extracts of radioiodinated male and female gametes. These surface proteins on gametes of both sexes of P. gallinaceum thus appear to include target antigens of anti-gamete transmission blocking immunity.
Alloantigens placed into the anterior chamber of the eye induce specific suppression of delayed-type hypersensitivity but normal cytotoxic T lymphocyte and helper T lymphocyte responses.
Authors: Niederkorn J Y , Streilein J W
Published: December 2022

Intracameral inoculation of allogeneic B16F10 melanoma cells (C57BL/6) into LP/J mice resulted in progressively growing intraocular tumors and impaired delayed-type hypersensitivity (DTH) reactivity. Additional experiments showed that DTH responses were specifically down-regulated by splenic T suppressor cells. By contrast, subcutaneous inoculation of B16F10 melanoma cells induced significant DTH responses to the alloantigens expressed on the tumor cells and stimulated brisk rejection of the subcutaneously injected tumor cells. In spite of the T suppressor cell inhibition of DTH reactivity, significant cytotoxic T lymphocyte activity could be demonstrated in lymphoid cell suspensions from hosts harboring allogeneic intraocular tumors. The demonstrated cytotoxic T lymphocyte activity is particularly noteworthy because it occurs in the face of severely suppressed DTH responsiveness and thus implies that the intracameral presentation of alloantigens evokes a precise immunoregulatory process that selectively and concomitantly modulates specific cellular immune components; one immune process (cytotoxic T lymphocyte function) is stimulated whereas the other (DTH responsiveness) is down-regulated.
Studies on the mechanism of the human natural killer cell lethal hit: analysis of the mechanism of protease inhibition of the lethal hit.
Authors: Hiserodt J C , Britvan L , Targan S R
Published: December 2022

The terminal killer cell-independent lysis (KCIL) stage of the human natural killer (NK) lethal hit is blocked by the protease enzymes trypsin (T), chymotrypsin (CT), and papain (P). The present studies analyze the mechanism of inhibition of KCIL by these enzymes. The pretreatment of effector PBL with T or CT but not P effectively reduced the ability of these cells to mediate NK lysis. This was due at least in part to a reduced ability of the treated NK cells to bind the NK target K562. Pretreatment of K562 cells with T, CT, or P also abolished their ability to serve as targets due to reduced binding ability. These same enzyme-pretreated target cells, however, were unaffected in their ability to bind a natural killer cell-derived cytolytic factor (NKCF) molecule(s), as determined by direct NKCF absorption studies or by their ability to cold target compete for the binding of NKCF to another NKCF-sensitive cell, the L929 fibroblast, thereby indicating that the K562 "target antigen" and the NKCF-receptor are independently expressed structures. Furthermore, NKCF activity, as measured by its ability to kill either K562 or L929 cells, was sensitive to T and CT but resistant to P. These studies indicate that various proteases inhibit NK-KCIL by different mechanisms and suggest that the lethal hit is a complex process. The ability of P to inhibit KCIL but not affect NKCF activity or the target cell NKCF receptor implies that additional NK cell-derived materials may be required in the lethal hit during direct NK cell-mediated cytotoxicity. A model depicting a hypothetical molecular mechanism for human NK cytolysis is presented and discussed.
Inhibition of RNA synthesis by deoxyadenosine plus deoxycoformycin in resting lymphocytes.
Authors: Matsumoto S S , Yu J , Yu A L
Published: December 2022

Deoxyadenosine has been implicated in the lymphocytopenia that occurs in immunodeficient children with an inherited deficiency of adenosine deaminase (ADA) and in leukemic patients treated with the ADA inhibitor deoxycoformycin. The recent reports of deoxyadenosine toxicity to nondividing lymphocytes indicates a challenge to the mechanism for deoxyadenosine toxicity, which involves the inhibition of ribonucleotide reductase by dATP, leading to the inhibition of DNA synthesis. This study provides evidence for the inhibition of transcription by deoxyadenosine as an alternative mechanism of toxicity. The incubation of resting peripheral blood lymphocytes with deoxyadenosine plus deoxycoformycin led to an inhibition of uridine incorporation. The extent of inhibition increased with the increasing time of incubation and concentration of deoxyadenosine. Replacement of deoxyadenosine with other nucleosides, adenosine or deoxyguanosine, had no effect, suggesting that deoxyadenosine-induced inhibition was not due to the reduced transport of uridine. Separation of DNA from RNA by differential alkaline hydrolysis showed that the reduction of uridine incorporation was primarily in the RNA fraction. The time sequence of the reduction in uridine incorporation coincided with that of the accumulation of dATP, but preceded that of ATP depletion and cell lysis. The phosphorylation of uridine into UTP was slightly reduced by deoxyadenosine, but this could not entirely account for the reduced incorporation of uridine into RNA. Finally, the direct measurement of RNA synthesis by the incorporation of UTP into isolated nuclei showed that RNA synthesis was inhibited to 88% and 41% of control values in lymphocytes preincubated with 20 microM deoxyadenosine for 3 and 15 hr, respectively. These findings demonstrate that deoxyadenosine plus deoxycoformycin inhibits RNA synthesis in resting lymphocytes.
Characterization with monoclonal antibodies of T lymphocytes bearing Fc receptors for IgE (T epsilon cells) and IgG (T gamma cells) in atopic patients.
Authors: Thompson L F , Mellon M H , Zeiger R S , Spiegelberg H L
Published: December 2022

Peripheral blood T lymphocytes from nonatopic control donors, asymptomatic atopic donors, and patients with moderate to severe atopic dermatitis were analyzed for Fc receptors for IgE (T epsilon cells) and IgG (T gamma cells) by rosette assays and were characterized with monoclonal antibodies. The T cells were reacted first with monoclonal antibodies, followed by fluoresceinated F(ab')2 goat antimouse Ig; they were then rosetted, and subsequently the rosetting cells were examined for immunofluorescence. Seven nonatopic control donors had less than 0.1% T epsilon cells and a mean +/- SD of 10.5% +/- 4.1 T gamma cells. Seven asymptomatic atopic donors with low IgE levels (2 to 233 IU/ml) varied from less than 0.1 to 1.3% T epsilon cells and 7.2% +/- 3.7 T gamma cells. Six of seven patients with moderate to severe atopic dermatitis and IgE levels of 1339 to 24,261 IU/ml had less than 0.1% T epsilon cells and significantly fewer T gamma cells (3.1% +/- 2.7, p less than 0.01) than the nonatopic control donors and the atopic donors in remission. Both T epsilon and T gamma cells reacted with the pan-T cell antibody Lyt-3 (anti-sheep red cell receptor) but not with antibodies OKT3, OKT4, or OKT6. Subpopulations of both T epsilon and T gamma cells reacted with antibodies OKT8 and the antimonocyte antibody OKM1. The OKM1+ cells did not appear to be monocytes, however, because the T cells did not react with another antimonocyte antibody, BRL.2, and were negative for nonspecific esterase activity. (ABSTRACT TRUNCATED AT 250 WORDS)
Spontaneous and induced interferon production by peripheral blood mononuclear leukocytes from humans with herpes labialis.
Authors: Green J A , Weiss P N , Spruance S L
Published: December 2022

Peripheral blood mononuclear leukocytes (PBML) were obtained from 44 individual human subjects within 1 to 66 days after the onset of an episode of recurrent herpes labialis. PBML did not spontaneously produce interferon (IFN) when maintained in cultures that contained medium only. Absence of detectable IFN could not be explained by delayed kinetics of production because no appreciable IFN was present in medium from 5-day-old cultures. IFN was produced when PBML were exposed to Newcastle's disease virus or to phytohemagglutinin. These findings suggest that spontaneous IFN production may not occur predictably after an episode of herpes labialis.
Anti-idiotypic antibodies to HLA-DR4 and DR2.
Authors: Reed E , Bonagura V , Kung P , King D W , Suciu-Foca N
Published: December 2022

The aim of our study was to determine whether antibodies recognizing epitopes of HLA-DR antigens (idiotypic antibodies or Ab1) induce the production of anti-idiotypic antibodies (Ab2). We tested the capacity of the F(ab')2 fragment obtained from two sera, one with no anti-HLA antibodies (serum ES) and one depleted by absorption of anti-HLA lymphocytotoxins (serum FH), to block the anti-DR antibodies reacting with the HLA-DR antigens of the immunizing donor. The F(ab')2 fragment obtained from serum ES inhibited the anti-DR2 activity of an earlier post-delivery bleeding obtained from the same woman. The anti-idiotypic antibodies contained by this serum also inhibited the anti-DR2 activity of a reference anti-DR2 antiserum 8W907 and of an anti-MT1 antiserum 8W1231. Similarly, the F(ab')2 fragment obtained from serum FH, after absorption of her anti-DR4 antibody, inhibited the anti-DR4 activity of autologous and homologous antisera. These data suggest that sera of parous women contain anti-idiotypic antibodies directed against regulatory idiotypes of anti-DR antibodies.
Separation of the immune response genes for LDH-B and MOPC-173. I. Description of an immune response defect in B10.BASR1.
Authors: Gutmann D H , Allen P M , Niederhuber J E
Published: December 2022

By using the intra-I-region recombinant mouse strain, B10.BASR1 (H-2as4), the immune response (Ir) genes for LDH-B and MOPC-173 were genetically and serologically separated, as assayed by T cell proliferation. Previous work demonstrated that the H-2s and H-2b strains respond to LDH-B and MOPC-173, whereas the H-2a and H-2k strains failed to respond due to haplotype-specific suppression of I-Ak-activated T helper cells by I-Ek-activated T suppressor cells. In the experiments reported here, B10.BASR1 mice, which lack I-Ek expression, mounted a significant T cell proliferative response to MOPC-173 but not to LDH-B. Separation of the Ia determinants used in restricting these two antigen responses was further confirmed when pretreatment of B10.S(9R) (A alpha sA beta sE beta sJk) macrophages with A.TL anti-B10.HTT (anti-A beta sE beta sJs) serum absorbed with B10.BASR1 spleen cells blocked the LDH-B response but not the MOPC-173 response. Unabsorbed serum blocked both antigen responses. The primary immunogenic determinant recognized by LDH-B or MOPC-173 immune T cells was not present on both antigens, as MOPC-173-primed T cells and LDH-B-primed T cells responded only to the priming antigen. Lastly, by using the A beta mutant strain, B6CH-2bm12, it was shown that the Ir gene and Ia determinants affected by this mutation had no effect on the LDH-B and MOPC-173 proliferative responses. These results suggest the possibility of an intragenic recombinatorial event in either the A alpha or A beta chain resulting in the separation of these two immune response gene functions.
Selective killing of target cells by antibody-ricin A chain or antibody-gelonin hybrid molecules: comparison of cytotoxic potency and use in immunoselection procedures.
Authors: Colombatti M , Nabholz M , Gros O , Bron C
Published: December 2022

Ricin A chain and gelonin, two plant proteins that can powerfully reduce the protein synthetic capacity of ribosome preparations, were covalently coupled to a monoclonal anti-Thy-1.2 antibody. Two conjugates were prepared by using N-succinimidyl-3-2(-pyridyldithio)propionate, which generates a disulfide linkage between the component molecules. Both conjugates specifically killed Thy-1.2 antigen-bearing EL-4 cells, but had no effect on Thy-1.2- BW5147 cells. The cytotoxic potency of both reagents was determined by comparing the cloning efficiency of E1-4 target cells after treatment with the conjugate. The frequency of cells surviving treatment with 45 micrograms/10(6) cells of the gelonin conjugate was 1/72, whereas this frequency was 1/836 after exposure to 7 micrograms of the Ricin A chain conjugate. Both reagents could be successfully used to select Thy-1.2- cells from cell mixtures consisting of Thy-1.2+ and Thy-1.2- cells.
MHC determinants of response to Rh immunization.
Authors: Raum D D , Awdeh Z L , Page P L , Yunis E J , Alper C A
Published: December 2022

The demonstration of immune response genes in man has been difficult, although there is evidence for genes linked to the MHC in mouse and guinea pig that control both the specificity and magnitude of immune responses. A number of features of the antibody response to the Rh D antigen, such as the failure of some individuals at risk to respond, the restricted immunoglobulin class, subclass, and light chain type of the antibody produced, and the presumed minor structural difference between Rh D antigen and its allelic product, all suggest that one or at most a few immune response genes are involved. Typing for the four MHC-linked complement genes BF, C2, C4A, and C4B was carried out in 52 independently ascertained Caucasian individuals with significant anti-D titers. A control population of 623 normal Caucasian chromosomes was also studied. In patients with anti-D antibodies, the frequency of BF F1 (0.04 vs 0.0064 for 623 chromosomes, p less than 0.003); of C4A 3 (0.769 vs 0.631, p less than 0.006); and of C4B Q0 (0.25 vs 0.104, p less than 0.00004) were all increased. These three alleles are found in the common complotype BF 8F1,C2 C,C2A 3, C4B Q0, and presumably represent a single extended haplotype of 6p associated with (and presumably containing a gene for) the immune response to RhD. This complotype has a 0.6% frequency in 623 normal control chromosomes, but is also increased in patients with insulin-dependent diabetes mellitus and with membranous glomerulonephritis.
Sequential requirements for cell cycle progression of resting human B cells after activation by anti-Ig.
Authors: Muraguchi A , Kehrl J H , Butler J L , Fauci A S
Published: December 2022

We have previously demonstrated that in vivo activated normal human B cells reflected differential sensitivity on the basis of cell size to either an activation signal delivered by anti-mu or a proliferative signal delivered by a monoclonal B cell growth factor (BCGF) produced by a human T-T hybridoma. In this manuscript, we have shown that by using an in vitro co-culture system of stimulation with anti-mu and BCGF, purified small (resting) B cells could be induced by anti-mu stimulation to express functionally active BCGF acceptor sites concomitant with RNA synthesis and cell enlargement. We have demonstrated that purified small B cells could be activated to increase both cell size and RNA synthesis within 8 hr of anti-mu stimulation. DNA synthesis by anti-mu-stimulated B cells began at 36 to 44 hr from initial stimulation only when BCGF was added to the culture. In addition, large B cells that had been incubated with anti-mu for 24 to 48 hr manifested significant incorporation of [3H]thymidine if BCGF was added to cultures. These data strongly suggest that anti-mu may induce the G0 phase B cells into the G1 phase and that BCGF may then push at least a subset of these G1 phase-B cells into the S phase. This experimental system may provide a useful model of normal human B cell activation and proliferation and may allow a more precise delineation of each phase of this cascade in the B cell repertoire.
The accessory cell function of human alveolar macrophages in specific T cell proliferation.
Authors: Toews G B , Vial W C , Dunn M M , Guzzetta P , Nunez G , Stastny P , Lipscomb M F
Published: December 2022

The capacity of alveolar macrophages to support mitogen- and antigen-induced proliferation of autologous, monocyte-depleted T cells in normal, nonsmoking volunteers was studied. Purified T cells failed to proliferate in response to mitogen or antigen, whereas co-culture with peripheral blood monocytes restored responsiveness. Alveolar macrophages (AM) reconstituted the response of T cells to mitogen, indicating that AM can deliver a second proliferative signal. AM, however, were markedly inferior to monocytes in supporting antigen-induced proliferation. Thus, in 19 normal volunteers, the mean response of immune T cells to diphtheria toxoid in cultures reconstituted with normal AM was only 25% of the proliferative response to diphtheria in cultures with monocytes. Although four volunteers demonstrated antigen-presenting function equivalent to monocytes, in the remaining 15 antigen-presenting ability of AM was less than 15% that of monocytes. The difference in antigen-presenting function between AM and monocytes was not due to a difference in their display of HLA-D/DR determinants because 80% of AM were HLA-DR positive. The role of suppression in the diminished antigen-presenting function of AM was assessed in 12 volunteers utilizing mixing experiments. Eight volunteers demonstrated suppressor AM but four did not, suggesting that AM from at least some normal individuals have a faulty antigen-processing mechanism. Taken together, these studies demonstrate that AM may play three different roles in modulating T lymphocyte responses, i.e., they may present antigen, they may suppress normal responses, or they may remain immunologically inert. The factors that determine which function is expressed in vivo may determine the pulmonary response to inhaled antigen.
Prevention of granuloma development in the mouse by using T cell hybridoma products.
Authors: Ginsburg C H , Dambrauskas J T , Whitaker R B , Falchuk Z M , Greene M I
Published: December 2022

The ability of an azobenzenearsonate (ABA)-specific suppressor T cell factor, a soluble extract from first order suppressor T cells (Ts1), and suppressor molecules produced by a long-term T cell hybridoma to regulate ABA-specific granuloma formation was studied. ABA-derivatized syngeneic spleen cells (ABA-SC) administered subcutaneously induced persistent delayed-type hypersensitivity (DTH) responses, detected by footpad swelling and hapten-specific granuloma formation by 72 and 96 hr after challenge with ABA-bovine serum albumin coupled to polyacrylamide beads (ABA-BSA-PAB). Soluble factors from ABA-specific Ts1 prevented DTH and granulomatous development after subcutaneous administration of ABA-SC. Moreover, the in vivo administration of a factor that is derived from a Ts1 functioning hybrid cell line induced a second set of suppressor cells (Ts2) that upon transfer to syngeneic ABA-primed mice were able to inhibit granuloma formation in the footpad, as well as in the gastrointestinal tract after challenge with ABA-BSA-PAB. These experiments demonstrate the dependence of the granulomatous reaction on T cell-mediated events, as well as the potential therapeutic efficacy of an antigen-specific suppressor T cell factor and a hybridoma T cell product in limiting antigen-specific granuloma formation in vivo.
Cell surface antigens expressed by subsets of pre-B cells and B cells.
Authors: McKearn J P , Baum C , Davie J M
Published: December 2022

A large number of monoclonal antibodies, produced by immunizing rats with mouse pre-B cell lines, have been analyzed for their ability to define cell surface antigens expressed by B cells at early stages of differentiation. Whereas many antibodies recognized antigens on pre-B cell lines, only two clones detected cell surface antigens that were distinguished by their restricted distribution among a panel of continuous cell lines and cells from various tissues. Monoclonal antibody clone AA4.1 recognized a cell surface antigen found on all pre-B lymphomas and on one of three B lymphomas tested. This antigen was found on cells at highest frequency in the bone marrow. Adult spleen and fetal liver also have detectable numbers of AA4.1+ cells. Cells that did not express this antigen include plasmacytomas, two of three B lymphomas, T lymphomas, a stem cell line, adult liver, brain, thymus, and lymph node cells. Clone GF1.2 detected an antigen on some pre-B cell lines, one of three B lymphomas tested, and a small fraction of cells from adult bone marrow, spleen, lymph node, and fetal liver. Plasmacytomas, some pre-B lymphomas, two B lymphomas, T lymphomas, adult liver, brain, and thymus cells were negative. In adult bone marrow, AA4.1 bound to all cytoplasmic IgM+ pre-B cells, whereas GF1.2 detected one-half of these cells. Both antibodies recognized approximately 50% of surface IgM+ (sIgM+) bone marrow cells. A small population of bone marrow cells lacking any detectable Ig (surface or cytoplasmic) also reacted with these antibodies. Depletion of AA4.1 or GF1.2 antigen-bearing cells from bone marrow reduced the ability of bone marrow B cells to respond to LPS by 50 to 65%. Experiments with a cloned pre-B lymphoma demonstrate that AA4.1+ pre-B cells become sIgM+ GF1.2+ B cells after activation with LPS. These antibodies recognize cell surface determinants with restricted distribution among the B lymphocyte lineage because they detect antigens displayed by normal and transformed immature B lymphocytes.
In vitro stimulation of C3H/HeJ spleen cells and macrophages by a lipid A precursor molecule derived from Salmonella typhimurium.
Authors: Vogel S N , Madonna G S , Wahl L M , Rick P D
Published: December 2022

C3H/HeJ mice possess a genetic lesion that renders them significantly less responsive to the biologic effects of protein-free lipopolysaccharide (LPS) preparations, and more specifically, to the lipid A region of the LPS molecule. The in vivo manifestations of this mutation are also reflected in vitro in that cells derived from this mouse strain fail to respond to LPS when compared with cells derived from fully endotoxin-responsive mouse strains. The precise nature of this gene defect has not yet been established. In this study, we have examined in vitro the biologic activities of a structurally less complex "lipid A precursor" molecule, produced by a conditionally lethal, temperature-sensitive mutant of Salmonella typhimurium. In contrast to the intact LPS or wild-type lipid A extracted from the parental strain of Salmonella typhimurium, the lipid A precursor induced a highly significant, polymyxin B-inhibitable mitogenic response in splenic cultures derived from LPS-hyporesponsive C3H/HeJ and C57BL/10ScN (nu/nu) mice. In addition, the lipid A precursor was found to stimulate cultures of C3H/HeJ macrophages to produce significant levels of both interleukin 1 (IL 1, previously referred to as "lymphocyte activating factor" or "LAF") and prostaglandins of the E series (PGE). These findings suggest the possibility that the defect in endotoxin responsiveness exhibited by C3H/HeJ mice may be related to a defect in the processing of wild-type lipid A or LPS to a suitably stimulatory form that is structurally related to the lipid A precursor molecule.
Selective transport of serum-derived IgA into mucosal secretions.
Authors: Sheldrake R F , Husband A J , Watson D L , Cripps A W
Published: December 2022

The relative contribution of serum-derived and locally produced IgA has been estimated in sheep mammary secretion at various stages of lactation by comparing the transport of radiolabeled IgA and IgG2 from serum to secretions. During early and mid-lactation, but not during involution, serum IgA was selectively transported to mammary secretion on a large scale; in comparison, there was no transport of serum IgA into intestinal secretion. Estimates of local production indicated that the bulk of the IgA in mammary involution secretion and intestinal secretion was locally produced, whereas there was no evidence for local production of IgA in early or mid-lactation secretion. Our studies reveal an inverse relationship between the extent of local production of IgA by plasma cells underlying secretory epithelia and the selective transport of IgA from serum. This finding suggests that selective transport of serum IgA occurs at a number of mucosal sites, but is dependent on secretory component availability, because where local production is predominant, there are fewer secretory component molecules available for serum IgA transport. For this reason, bile transport of IgA does not represent a unique mechanism for the removal of IgA from serum.
Effect of erythrocyte membrane modulation by lysolecithin on complement-mediated lysis.
Authors: Silverman B A , Weller P F , Shin M L
Published: December 2022

Alterations of the physiochemical properties of membranes, such as acyl chain length of phospholipids, cholesterol content, and disturbance of the bilayer packing, affect the efficiency of membrane attack by C5b-9. In the present study, we explored the effect of lysolecithin (LL), a naturally occurring derivative of membrane phospholipids, on membrane damage by C5b-9. Sublytic doses of the L isomer of palmitoyl-lysolecithin were incorporated into the erythrocyte membranes of guinea pig (gpE) or sheep (shE) and the cells were then lysed with C5b6-C9. Marked enhancement of complement-mediated lysis was observed with LL-treated gpE after 2 hr of incubation, whereas the lytic enhancement was either nil or only marginal in shE. Studies on the kinetics of LL incorporation and metabolism in gpE membranes with 14C-LL showed that LL was rapidly incorporated and catabolized to generate free fatty acid (FA). Maximal accumulation of labeled FA in the membrane and loss of membrane-incorporated LL, resulting in approximately equimolar amounts of LL and FA, occurred at 2 hr, concomitant with enhancement of complement-mediated lysis. In shE such a breakdown of LL occurred only minimally. This quantitative difference in LL breakdown between gpE and shE was in accord with lysophospholipase activity that was two and one-half to seven times more active in gpE than shE membranes. When an ether-linked analog of LL (1-O-hexadecyl-sn-phosphorylcholine), which is resistant to lysophospholipase, was incorporated in gpE, the lytic enhancement was not observed. The results of our experiments indicate that the membrane modulating effect of LL on lysis by C5b-9 requires the enzymatic breakdown of LL.
Use of monoclonal antibodies against factor H to investigate the role of a membrane-associated protein antigenically related to H in C3b-receptor function.
Authors: Schulz T F , Scheiner O , Alsenz J , Lambris J D , Dierich M P
Published: December 2022

Three murine monoclonal IgG1 kappa-antibodies, MAH-1, MAH-2, and MAH-3, were raised against factor H purified from human plasma. In cross-inhibition studies MAH-3 did not compete with MAH-1 and MAH-2, and vice versa, for the binding to H, whereas MAH-1 and MAH-2 inhibited each other. MAH-1 and MAH-2 inhibited the binding of H to C3b attached to an ELISA plate as well as to C3b bound to sheep erythrocytes by means of the classical pathway convertase and of C3b to H attached to an ELISA plate. The determinant defined by MAH-1 and MAH-2 was no longer accessible on H bound to C3b. In contrast, MAH-3 interfere with the binding of H to C3b or vice versa only to a smaller extent but recognized a determinant still accessible on H bound to C3b and was able to agglutinate EAC14o23b-H in an indirect Coombs test. All three antibodies were shown to bind to tonsil cells and Raji cells in an indirect cell ELISA. The membrane-associated molecule detected by these antibodies had an apparent m.w. of 140,000 D in SDS-PAGE. All three antibodies partially inhibited the binding of EAC14o23b to tonsil lymphocytes and, in the presence of 0.1 mM DFP, to Raji cells; binding of EAC14o23bi and EAC14o23d to tonsil cells was not affected. We conclude that MAH-3 recognizes a determinant distinct from the ones recognized by MAH-1 and MAH-2, the latter possibly defining identical epitopes that are located close to the binding site for C3b. The fact that these two distinct epitopes could be detected on a 140,000-D membrane-associated protein from lymphoid cells strongly suggests that this molecule is at least antigenically related to serum H and shares with H a region carrying the binding site for C3b. The rosette inhibition studies imply that this structure is important for the binding of C3b-coated particles to lymphoid cells.
An antigen-activated DFP-inhibitable enzyme controls basophil desensitization.
Authors: Kazimierczak W , Meier H L , MacGlashan D W , Lichtenstein L M
Published: December 2022

Diisopropyl fluorophosphate (DFP), an inhibitor of serine esterases, enhances IgE-mediated histamine release from human basophils and blocks the desensitization process (i.e., the antigen-induced hyporesponsiveness) in these cells. Both activities occur at relatively low concentrations of DFP (0.1 to 0.5 mM) and are dependent on an antigen-activated intracellular event: if DFP is removed before antigen addition, it has neither effect. Neither hydrolyzed DFP nor the non-phosphorylating diisopropyl methyl phosphate enhanced histamine release or blocked desensitization. In addition to providing a demonstrable biochemical correlate of desensitization, our data suggest that the desensitization process controls the release of mediators of allergic reactions.
Prophylactic immunization against experimental leishmaniasis. III. Protection against fatal Leishmania tropica infection induced by irradiated promastigotes involves Lyt-1+2- T cells that do not mediate cutaneous DTH.
Authors: Liew F Y , Howard J G , Hale C
Published: December 2022

Protective immunity against fatal L. tropica infection in genetically vulnerable BALB/c mice can be induced by prophylactic immunization with irradiated promastigotes even when heat-killed. Such immunity is adoptively transferable transiently into intact or durably into sub-lethally irradiated (200 or 550 rad) syngeneic recipients by splenic T but not B cells. The effector T cells are of the Lyt-1+2- phenotype, devoid of demonstrable cytotoxic activity. The immune splenic T cell population expresses specific helper activity for antibody synthesis. A causal role for helper T cells in this capacity, however, seems unlikely, because it was shown in the accompanying paper that antibody does not determine the protective immunity against L. tropica. The immunized donors show no detectable cutaneous DTH or its early memory recall in response to live or killed promastigotes or a soluble L. tropica antigen preparation. Spleen, lymph node, and peritoneal exudate cells from protectively immunized donors similarly fail to transfer DTH locally or systemically. These cells also lack demonstrable suppressive activity against the expression or induction of DTH to L. tropica. Thus, protection against L. tropica induced by prophylactic i.v. immunization with irradiated promastigotes appears to be conferred by Lyt-1+2- T cells that are distinguishable from T cells mediating either both DTH and T help, or cytotoxicity.
Complete sequence of a cloned cDNA encoding rabbit secreted mu-chain of VHa2 allotype: comparisons with VHa1 and membrane mu sequences.
Authors: Bernstein K E , Alexander C B , Reddy E P , Mage R G
Published: December 2022

The complete sequence of a cDNA clone (pmu3) encoding a secreted IgM heavy chain from a rabbit of VHa2 allotype has been determined. Comparison of the nucleic acid and amino acid sequences with a comparable mouse mu-chain shows unusually high homologies of the sequences of the fourth domains and secretory portions of the molecules (80 to 90% vs 56 to 73% for the other domains). This high degree of homology is also seen with the sequences of the fourth domain and secreted terminus of human mu-chain. The DNA sequence of a second cDNA clone encoding the membrane form of rabbit IgM is approximately 90% homologous with the mouse and human coding sequences for the membrane terminus, and there is 98 and 97% amino acid sequence homology. We found an unusually long (156 base pair) 5' untranslated region in clone pmu3 and discovered that 105 bases at the 5' end were complementary to the terminal portion of the CH4 domain of our mu sequence. Southern blotting analyses and the finding of a 13 base pair segment in rabbit genomic V region DNA that is homologous to the complementary strand of a segment of the CH4 of rabbit mu strongly suggests that this extended sequence resulted from a reverse transcriptase "hooking error". We have also obtained and sequenced another cDNA clone from a VHa1 cDNA library. Comparison of the V region of clone pmu3 from VHa2 with the 117 available positions of a1 DNA sequence shows 25 differences, nine of which are in allotype-associated codons. There is also a two-codon deletion in the VHa1 compared to VHa2 in the third framework region that may contribute to allotypic differences. Development of VHa allotype-specific probes, now in progress, is complicated by the fact that most of the allotype-associated amino acids of a1, a2, and a3 can be derived from each other by single base changes.
Effect of mouse interferon on the expression of a porcine major histocompatibility gene introduced into mouse L cells.
Authors: Satz M L , Singer D S
Published: December 2022

Mouse L cells transformed with a swine genomic clone, which encodes a major histocompatibility (MHC) antigen (SLAd), stably express SLAd on their surface. Mouse interferon (IFN) markedly enhances the expression of the heterologous SLAd as well as endogenous H-2k antigens in two independent transformants, as measured by flow microfluorometry. The expression of an unrelated surface antigen, gp70, is not affected. The increased expression of SLAd antigens is the result of an increased pool of SLA mRNA in IFN-treated cells. In vitro nuclear transcription experiments suggest that this increased accumulation of SLA mRNA results largely from an enhanced transcription of the heterologous SLA gene. The effect of IFN is not restricted to the MHC coding sequences; the transcription of two DNA sequence elements flanking the SLA gene, which are constitutively expressed in one L cell transformant, is also enhanced by IFN. In contrast, in another transformant these same flanking sequences are not transcribed and do not respond to IFN. The results suggest that IFN enhances the transcription of MHC coding and the flanking sequences that are expressed in its absence, but it does not appear to induce do novo transcription of the silent flanking genes examined.
Analysis of surface mu-chain expression in human lymphoblastoid cell lines that do not produce light chains.
Authors: Hendershot L , Levitt D
Published: December 2022

It has been suggested that light chains (LC) are necessary for the surface expression of mu heavy chains. Fluorescent antibody screening of 42 human lymphoblastoid cell lines transformed in our laboratory, however, disclosed four lines that expressed surface mu-chains without LC. The biosynthesis, glycosylation, and turnover of mu-chains in these cell lines was compared to mu-chain production in cell lines synthesizing both heavy chains and LC. LC production could not be detected in the mu +LC- cell lines by either surface or biosynthetic labeling. The mu-chains expressed on the surface of the LC- cells appeared as disulfide-linked dimers and migrated slightly faster on SDS-polyacrylamide gels (70 Kd) than did mu-chains from IgM monomers (H2 L2) (78 Kd) after reduction. Biosynthetic labeling in the presence of tunicamycin demonstrated that the smaller size of free mu heavy chains was due to incomplete glycosylation of these molecules and not to amino acid deletions. The mu-chains produced by mu + LC- cells lines were degraded faster than mu-chains from LC+ cell lines, but their rate of transit to the cell surface was identical in both cell types. Thus, although LC are necessary for the formation of an intact antigen-binding site, they are not involved in the synthesis or expression of membrane mu-chains.
Cytotoxic T lymphocyte recognition of HLA-A/B antigens introduced into EL4 cells by cell-liposome fusion.
Authors: Engelhard V H , Powers G A , Moore L C , Holterman M J , Correa-Freire M C
Published: December 2022

HLA-A2 and -B7 antigens were introduced into EL4 (H-2b) cells by cell-liposome fusion and were used as targets or stimulators for cytotoxic T lymphocytes (CTL) generated in C57B1/6 (H-2b) mice. It was found that such EL4-HLA cells were not recognized by CTL that had been raised against either a human cell line bearing these HLA antigens or the purified HLA-A2 and -B7 antigens reconstituted into liposomes. In addition, EL4-HLA cells were not capable of inducing CTL that could recognize a human cell line bearing HLA-A2 and -B7 antigens. Instead, EL4-HLA cells induced CTL that specifically lysed EL4-HLA cells and not human cells expressing HLA-A2 and -B7. CTL recognition required the presence of HLA antigens on the EL4 cell surface and was inhibited by antibodies against either H-2b or HLA-A/B. Monoclonal antibody binding studies showed that the expected polymorphic determinants of the HLA-A2 and -B7 antigens were still present on EL4-HLA cells. However, the specificity of CTL or their precursors that are capable of recognizing HLA-A2 or -B7 was altered after these antigens became associated with the EL4 surface. Possible explanations for these results are discussed.
Immune reactivity and immunosuppressive intervention (TLI) in experimental nephritis. I. Immunopathologic correlates in the accelerated autologous form of nephrotoxic serum nephritis.
Authors: Lowry R P , Forbes R D , Blackburn J H
Published: December 2022

The progression of histologic changes observed in the accelerated autologous form of nephrotoxic serum nephritis (AA-NTSN) in the inbred LEW rat, ranging from minimal endocapillary proliferation to marked endo- and extra-capillary proliferation together with fibrin deposition and necrosis of glomerular tufts, was closely correlated (day 8) with parallel measures of albuminuria (1.6 leads to 280 mg/24 hr). In the induction phase of AA-NTSN (day 0) a direct linear correlation (r = 0.72, p less than 0.05) was obtained between anti-SGG antibody levels and 24-hr urine albumin excretion. Subsequent observations (day 7) yield an inverse correlation between anti-SGG antibody and albuminuria (r = -0.54, p less than 0.01), and this change was shown to be related to the loss of specific antibody in the urine (r = 0.59, p less than 0.025). Although splenic T cells of rats with AA-NTSN manifest a specific proliferative response to the inducing antigen SGG, and although the magnitude of this proliferative response (day 7) correlates directly with parallel measures of urine albumin excretion (r = 0.71, p less than 0.02), delayed-type hypersensitivity (DTH) to SGG measured by radiometric ear assay was inversely correlated with albuminuria in this model of experimental nephritis (r = 0.80, p less than 0.01). Additional data are presented that strongly suggest that persistent albuminuria at 1 mo after induction of AA-NTSN is independent of ongoing immunopathologic processes. Thus, glomerular injury in AA-NTSN, previously linked to prominent glomerular macrophage accumulation, is shown to be primarily dependent on a brisk antibody response to the planted heterologous (sheep) immunoglobulin, whereas cellular immunity, readily demonstrated in the splenic T cell compartment, is likely to be of lesser import in the pathogenesis of this lesion in the intact animal.
Regulatory interactions governing the proliferation of T cell subsets stimulated with pokeweed mitogen.
Authors: Puck J M , Rich R R
Published: December 2022

Serial phenotyping of human peripheral blood mononuclear cells (PBMC) cultured with pokeweed mitogen (PWM) demonstrated an excess of T8+ cells after stimulation. Preferential expansion of the T8+ cell compartment was a result of T8+ cell blast transformation while T4+ cells generated fewer blasts and tended to remain as small resting cells. When the proliferative behavior of T cell subsets in PWM-stimulated PBMC with physiologic proportions of T4+ and T8+ cells was compared with that of cultures depleted of T4+ or T8+ cells, two levels of regulation of proliferation were found: without T4+ cell help, T8+ cells were unable to divide; however, in the presence of T4+ cells, PWM-stimulated T8+ cells became potent feedback inhibitors of T4+ cell proliferation. The mechanism of suppression by PWM-activated T8+ cells of T4+ cell proliferation, not only to PWM, but also to tetanus toxoid, was pursued by measuring decreased interleukin 2 (IL2) recovery from cultures containing suppressors. Although passive absorption of IL2 by PWM-activated cells could contribute to the suppression of fresh proliferative responses, as shown directly with isolated T4+ cells induced by PWM to express IL2 receptors, a much more profound suppression was mediated by PWM-activated T8+ cells. The regulation of proliferative responses of helper and suppressor T cell subsets may determine the magnitude of their subsequent interactions and thus control the ultimate outcome of in vivo physiologic and pathologic immune responses.