bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental allergic encephalomyelitis in Lewis rats: immunoregulation of disease by a single amino acid substitution in the disease-inducing determinant.
Authors: Kardys E , Hashim G A 
Published: December 2022

Abstract
A single amino acid substitution in the sequence of the encephalitogenic determinant for Lewis rats destroyed its ability to induce experimental allergic encephalomyelitis (EAE) but generated a potent immunoregulatory sequence capable of suppressing the development of both clinical and histologic signs of EAE. The EAE-inducing determinant (synthetic peptide S6) H-Ala-Gln-Gly-His-Arg-Pro-Gln-Asp-Glu-Asn-OH (residues 75 to 84) of the bovine MBP induced clinical and histologic signs of EAE when it was administered at doses of 0.5 micrograms or higher. Gly substituted for the C-terminal Asn during the synthesis of peptide S6 generated the homologous sequence designated by peptide S79. Peptide S79 failed to induce either clinical or histologic signs of EAE even when it was administered at dosages up to 1000 times higher than those of S6. Similarly, rats pretreated with a single dose of S79 were not only unresponsive to an encephalitogenic challenge but also were capable of transferring unresponsiveness to syngeneic recipients with viable donor lymphocytes. The induction of unresponsiveness that was abrogated by pretreatment with cyclophosphamide suggests the development of an S79-sensitive lymphocyte subset that regulates MBP-induced EAE in Lewis rats.
Increased expression of I-region-associated antigen (Ia) on B cells after cross-linking of surface immunoglobulin.
Authors: Mond J J , Seghal E , Kung J , Finkelman F D 
Published: December 2022

Abstract
Both surface Ig (sIg) surface Ia (sIa) have been shown to have important roles in B lymphocyte activation. In order to investigate a possible relationship between these molecules, we studied the effects of cross-linking of sIg on the expression of sIa, as measured by fluorescence-activated cell sorter analysis of lymphoid cells stained with conventional anti-Ia anti-serum or with fluorescein-labeled anti-Ia antibodies. Exposure of cells for 24 hr in vitro to anti-delta, anti-mu, anti-kappa antibodies, or their F(ab')2 fragments induced a very dramatic increase in expression of sIa. Similarly, i.v. injection of anti-delta antibodies into adult mice induced a 2- to 3-fold increase in expression of B cell sIa on spleen, lymph node, and Peyer's patch lymphocytes. There was no increase under these conditions in expression of other B lymphocyte surface antigens, including H-2, 4B9, and 17C9. Furthermore, exposure of B lymphocytes to antibodies directed to B lymphocyte surface antigens other than sIg did not result in an increase in expression of sIa. The anti-Ig-induced increase in sIa expression appeared to be T independent, required cellular protein synthesis, and required more time to occur than did the cross-linking and removal of sIg. This increase in expression of sIa did not occur on B lymphocytes obtained from mice younger than 3 wk old. This increase in expression of sIa may reflect a proximal event in B lymphocyte activation that occurs after cross-linking of sIg by antigen and that may enhance subsequent cellular interactions involving B lymphocytes.
Activation of the fifth and sixth component of the complement system: similarities between C5b6 and C(56)a with respect to lytic enhancement by cell-bound C3b or A2C, and species preferences of target cell.
Authors: Hänsch G M , Hammer C H , Mayer M M , Shin M L 
Published: December 2022

Abstract
Brief shift of purified C5 and C6 at 0 degrees C to pH 6.4, followed by immediate neutralization, results in the generation of a factor, designated C(56)a, that lyses erythrocytes together with C7, C8, and C9. We compared C(56)a and C5b6 generated by an alternative-pathway convertase, with regard to their action on different target cells. We found tht C(56)a is similar to C5b6 in the following properties: 1) Together with C7, C(56)a forms a stable intermediate on either sheep or guinea pig erythrocytes. 2) Membrane-bound C3b, or A2C incorporated in the membrane, enhances lysis by C(56)a-9, as well as lysis by C5b6-9. We also found that the lysis of EC(56)a7 or EC5b67 intermediates by C8 and C9 depends on the species of the erythrocytes and the species of C8 and C9. Thus, lysis of sheep erythrocytes is more efficient with guinea pig C8 and C9 than with human C8 and C9. In the case of guinea pig erythrocytes, this relationship is reversed, i.e., these cells lyse more efficiently when human C8 and C9 are used. Enhancement of lysis by membrane-bound C3b or A2C does not abrogate this species incompatibility pattern.
Human large granular lymphocytes: spontaneous and interferon-boosted NK activity against adherent and nonadherent tumor cell lines.
Authors: de Landazuri M O , López-Botet M , Timonen T , Ortaldo J R , Herberman R B 
Published: December 2022

Abstract
Human natural killer (NK) cells against K-562 tumor cells have been morphologically identified as large granular lymphocytes (LGL). We have investigated whether LGL are also responsible for NK activity against a variety of adherent and nonadherent tumor cell lines. LGL-enriched fractions, obtained by centrifugation of nonadherent mononuclear cells on discontinuous density gradients of Percoll, contained high levels of spontaneous and interferon- (IFN) boosted NK activity against each of the target cells tested. In contrast, the LGL-depleted functions, which contain most of the typical small lymphocytes, were devoid of NK activity and did not develop appreciable activity after treatment with IFN. The ability of the different fractions to exert NK activity correlated with their capacity to form conjugates with nonadherent tumor cells. Reconstitution of the different fractions with macrophages did not increase the NK activity of already cytotoxic fractions and did not induce appreciable activity in the LGL-depleted fractions. On the other hand, mixtures of highly cytotoxic and nonreactive cell fractions did not reveal the presence of suppressor cells for NK in the nonreactive fractions. Taken together, our data demonstrate that both spontaneous and IFN-boosted NK activity is confined to the LGL-enriched fractions and suggest that LGL are the main effector cells exerting NK cytotoxicity against a variety of adherent as well as nonadherent tumor cell lines.
Analysis of HLA-DR antigens by using monoclonal antibodies: recognition of conformational differences in biosynthetic intermediates.
Authors: Shackelford D A , Lampson L A , Strominger J L 
Published: December 2022

Abstract
The monoclonal antibodies L203 and L227 were used to characterize Ia-like antigens on human B cell lines. The antibodies appear to recognize subsets of HLA-DR molecules on the cell line Raji, which is heterozygous for HLA-DR. However, by using L203 and L227, more than 1 DR-like molecule could not be clearly identified on the DRw8 homozygous cell line MADURA. The 2 antibodies did display different affinities for different forms of the same DR molecule. On DRw8 and cell lines of other DR types, L227 had a greater affinity than L203 for the biosynthetic intermediates of the DR heavy and light chains. L203 displayed a greater affinity than L227 for the mature forms of the DR subunits. The antibody L227 immunoprecipitated the denatured DR light chain, but not the heavy chain, suggesting that the antigenic determinant is on the light chain. The L203 and L227 determinants are not on the N-linked oligosaccharides, since both antibodies recognized nonglycosylated DR antigens from cells treated with tunicamycin. In contrast to the DRw8 homozygous cell line, it was found that DRw6 homozygous B cell lines express at least 2 DR light chains. A xeno anti-HLA-DR (anti-p23,30) serum and L203 recognized both light chains, whereas L227 precipitated only 1 of the 2. A model depicting the expression of the L203 and L227 antigenic determinants on the DRw8 molecule is discussed.
The dual interaction of prostaglandin E2 (PGE2) and interferon (IFN) on NK lytic activation: enhanced capacity of effector-target lytic interactions (recycling) and blockage of pre-NK cell recruitment.
Authors: Targan S R 
Published: December 2022

Abstract
In this study we addressed the question of whether the known NK activators prostaglandin E2 (PGE2) and interferon (IFN) can synergistically activate NK lysis and whether they potentiate the same or different subsets of NK cells. We demonstrated that the activation of NK lysis can be enhanced as well as blocked by the interaction of these 2 activators. The enhancement of activation was not due to recruitment of separate subsets of pre-NK cells, but rather the synergistic enhancement of the recycling capabilities of the same set of NK cells. There was a temporal relationship to this enhancement. That is, if PGE2 was added during cellular processing required for full expression of NK activation induced by IFN, pre-NK lytic potential was inhibited. If, on the other hand, PGE2 is added after completion of full expression of the IFN-induced activated lytic process, there is enhancement of recycling capabilities of the same number of NK cells.
Epidermal cell (keratinocyte)-derived thymocyte-activating factor (ETAF).
Authors: Luger T A , Stadler B M , Katz S I , Oppenheim J J 
Published: December 2022

Abstract
In order to determine whether keratinocytes play a role in the modulation of the immune response, we investigated the murine keratinocyte cell line Pam 212. In culture these cells generate a substance with a biologic activity that greatly enhances phytohemagglutinin-induced thymocyte proliferation. We have, therefore, called this substance epidermal cell thymocyte-activating factor (ETAF). This keratinocyte-derived supernatant activity is mainly produced at the onset of the logarithmic growth phase and is directly mitogenic for murine thymocytes. Although ETAF by itself exhibits no T cell growth factor activity, ETAF enhances Interleukin 2 production by mitogen-stimulated murine spleen cells. Murine ETAF is not genetically restricted and lacks species specificity since it decreases lectin-induced proliferation of human peripheral blood lymphocytes (as well as murine spleen cells) and also enhances the production of human Interleukin 2. The factor has a m.w. between 15,000 and 25,000 as determined by gel filtration and elutes as a single peak from anion exchange chromatography columns. The activity is maintained mainly at alkaline pH and is rapidly destroyed at temperatures above 60 degrees C. These observations suggest that epidermal cells may interact with the immune system by elaborating nonspecific factors that modulate lymphocyte proliferation and augment lymphokine production.
Requirement of adherent/phagocytic cells for the induction of F1 anti-parent cell-mediated lympholysis. I. Parental adherent splenocytes serve as stimulators.
Authors: Freimuth W W , Cudkowicz G 
Published: December 2022

Abstract
Primary F1 hybrid anti-parent T cell-mediated lympholysis (F1 alpha P CML), induced in mixed spleen cell cultures, is an immune response specific for self H-2 antigens. The cellular requirements for induction were investigated by depleting or enriching stimulator splenocytes of adherent/phagocytic cells. Relatively large numbers of parental cells that are adherent to Sephadex G-10 particles or to plastic surfaces, and phagocytic for carbonyl iron, were required for stimulation (approximately 10(5) purified stimulators for 3.5 X 10(6) responders). Such parental cells are resistant to gamma radiation (in vivo and in vitro) and hydrocortisone (in vivo), negative for Thy-1, and positive for I-A and I-E/C surface antigens. This subpopulation of macrophages includes the predominant or sole immunogenic parental cell type of the spleen for the F1 alpha P response. Whereas removal of adherent/phagocytic cells from parental splenocytes entailed loss of stimulatory activity for F1 responder T lymphocytes, this was not the case for allogeneic responders. The ability to induce allogeneic CML was, in fact, fully retained by depleted parental cells. Adherent/phagocytic cells of F1 responder origin were available for cellular interactions in all mixed spleen cultures, yet they were competent for presentation of alloantigens, but not of self antigens borne by parental cells other than macrophages. In conclusion, the cellular requirements for stimulation differ quantitatively and qualitatively in F1 alpha P CML as compared to allogeneic and other CML systems. The distinct requirements presumably relate to the generation of specific effectors that are autoreactive as opposed to reactive with foreign antigens.
Binding reactivity of C-reactive protein for polycations. II. Modulatory effects of calcium and phosphocholine.
Authors: Potempa L A , Siegel J N , Gewurz H 
Published: December 2022

Abstract
C-reactive protein previously was shown to selectively and reversibly precipitate with certain small polymers of arginine and lysine. In the present report, calcium was shown to inhibit this reactivity in a dose-dependent manner, in direct contrast to the requirement for calcium for precipitation of CRP with C-polysaccharide. However, in the presence of phosphocholine, CRP rapidly precipitated and formed stable complexes with the polycationic polymers in the otherwise inhibitory calcium concentrations. alpha-Glycerol-phosphocholine, unlike phosphocholine, did not reverse this inhibitory effect. These results extend the characterization of the binding reactivity of CRP for polycations and suggest a relationship between this binding site and the sites for calcium and phosphocholine. We propose that CRP-polycation interactions in the presence of phosphocholine may have physiologic significance during the acute inflammatory process.
Monoclonal anti-IgM can separate T cell from B cell proliferative responses in the frog, Xenopus laevis.
Authors: Bleicher P A , Cohen N 
Published: December 2022

Abstract
The role of SIgM+ lymphocytes in frog mitogen responses and mixed lymphocyte reactions was examined. A murine monoclonal antibody with specificity for Xenopus laevis IgM was produced. The anti-IgM activity was not inhibited by glycoproteins other than Xenopus IgM, but could be inhibited with periodate-treated frog IgM. Fluorescent microsphere-coupled anti-IgM was used to show that adult and larval thymocytes had few sIgM+ lymphocytes, whereas spleens contained 19 to 34% sIgM+ lymphocytes. The spleens of larvally thymectomized adults were greatly enriched for sIgM+ cells. Lymphocyte suspensions were depleted of sIgM+ cells by incubation of spleen cells on plastic Petri dishes coated with anti-IgM monoclonal antibody. Compared with unseparated controls, the nonadherent cells cultured in serum-free medium were enriched for Con A and PHA mitogen responses and mixed lymphocyte culture (MLC) reactivity. Nonadherent cells were partially depleted of LPS mitogen responsiveness. Depletion or enrichment of the mitogen response was not a result of changes in kinetics or dose-response characteristics of the cells. In 1% FCS-supplemented cultures, the LPS response was not depleted, whereas the PHA response was still enriched. Thus, thymus-dependent and thymus-independent mitogen and MLC responses can be separated by the criterion of sIgM positivity in this anuran species.
Limitations of recognition of modified-self by alloantigen-activated cytotoxic T lymphocytes.
Authors: Ballas Z K 
Published: December 2022

Abstract
Alloantigen-activated CTL from CBA (H-2k), but not from C57BL/6 (H-2b), mice were able to lyse autologous cells modified by incubation with TNP-HSA. Moreover, allogeneic CTL of the H-2k haplotype lysed syngeneic cells modified with high or low concentrations of TNBS. Allogeneic CTL of the H-2b haplotype, however, did not lyse autologous cells modified with low concentrations of TNBS, even though they lysed syngeneic cells modified with high concentrations of TNBS. These limitations of recognition by the different H-2 haplotypes paralleled the restrictions evident for MHC-restricted, TNBS-specific CTL. It was thus apparent that alloantigen-activated CTL are governed by the same limitations of recognition operant for the MHC-restricted, TNBS-specific CTL.
Genetics of susceptibility to pristane-induced plasmacytomas in BALB/cAn: reduced susceptibility in BALB/cJ with a brief description of pristane-induced arthritis.
Authors: Potter M , Wax J S 
Published: December 2022

Abstract
BALB/cAn and BALB/cJ inbred strains of mice were separated 43 yr ago, but are still very closely related because they carry the same allelomorphs at many loci. When injected 3 times i.p. with 0.5 ml of pristane (2, 6, 10, 14 tetramethylpentadecane) 11% of strain BALB/cJ develop plasmacytomas in contrast to 61% in BALB/cAn sublines. BALB/cJ first injected with pristane as neonates also developed a reduced number of plasmacytomas as compared with BALB/cAn. About 20% of pristane-treated BALB/cAn and 70% of pristane-treated BALB/cJ develop arthritis, which first appeared in the ankle joints after a latent period of 4 mo or more.
Opsonization of pneumococci. II. Metabolic effects of a "third" human serum activity that mediates intracellular killing.
Authors: Guckian J C , Cavallo T , Fine D P 
Published: December 2022

Abstract
We investigated the mechanisms by which a serum activity, neither complement nor immunoglobulin, mediates killing of pneumococci by polymorphonuclear leukocytes (PMN). Electron microscopy revealed type 25 pneumococci to be within PMN when incubated in normal serum, in serum absorbed twice at 0 degrees C with type 25 pneumococci, or in absorbed plus heat-inactivated serum. Uptake of radiolabeled bacteria, and activation of oxygen consumption and of the hexose monophosphate shunt by PMN with pneumococci, were similar in normal serum, absorbed serum, or the combination of absorbed and heat-activated serum. Reduction of nitroblue tetrazolium (NBT) and of cytochrome c by PMN in the presence of type 25 pneumococci and absorbed serum, with or without heat-inactivated serum were one-third and one-half, respectively, of those in normal serum. Likewise, protein iodination was one-half that in normal serum. Reduction of cytochrome c by cytochalasin B-treated PMN was the same in normal, absorbed, or absorbed plus heat-inactivated serum. Furthermore, release of beta-glucuronidase from PMN after ingestion of pneumococci in 10% normal, absorbed, or absorbed plus heat-inactivated serum was identical. These data indicate that the "third" serum activity is not necessary for attachment of pneumococci to or ingestion by PMN, nor is it necessary for stimulation of the plasma membrane oxidase. Rather, it functions somehow in intracellular killing.
Spontaneous release of a factor with properties of T cell growth factor from a continuous line of primate tumor T cells.
Authors: Rabin H , Hopkins R F , Ruscetti F W , Neubauer R H , Brown R L , Kawakami T G 
Published: December 2022

Abstract
A continuous lymphoid cell line had been previously established from a gibbon with spontaneous lymphosarcoma. This cell line, designated as MLA144, when tested after several years in culture was shown to release spontaneously a factor biologically and biochemically similar to human T cell growth factor (TCGF). Conditioned media (CM) from MLA144 cells support growth and DNA synthesis of T cells from humans, several other species of primates, and also from mice and rabbits. The activity in the MLA144 CM is resistant to 60 degrees C and to low and high pH, has a m.w., as determined by gel filtration, of 21,500, elutes from DEAE-cellulose at 0.04 to 0.06 M sodium phosphate buffer, pH 7.6, and has an isoelectric point of about 6.45. Surface-marker analysis of MLA144 cells by rosetting techniques indicates that they are T cells lacking in the receptor for the Fc portion of IgG. The release of TCGF by MLA144 cells should have practical value in terms of ease of TCGF production and should be of great help in the facilitation of studies on the cell biology and molecular biology of TCGF production.
Studies on natural killer (NK) cells. II. Serologic evidence for heterogeneity of murine NK cells.
Authors: Burton R C , Bartlett S P , Kumar V , Winn H J 
Published: December 2022

Abstract
NK cells are divided into 2 subclasses on the basis of cell surface antigens: NKA cells, which preferentially lyse lymphoma cells and which are readily destroyed by treatment with anti-H-2, rabbit anti-mouse, or anti-NK specific antibodies in the presence of C; and NKB cells, which preferentially lyse nonlymphoma tumor cells and which are resistant to anti-NK specific antibodies, partially sensitive to anti-H-2 specific antibodies, and only fully sensitive to rabbit anti-mouse serum and C. Thus, suspensions of spleen cells that were treated with anti-NK-1.2 antibodies and C lost virtually all lytic activity for 6 lymphoma cell lines, whereas lytic activity for 2 nonlymphoma cell lines remained largely intact. It must be noted, however, that unlike NK-1.2 expression, target cell preference is not an absolute indicator of NK cell subclass. Cytotoxic T cells were readily distinguished from NKA and NKB cells on the basis of their sensitivity to monoclonal anti-Thy-1.2 antibodies and resistance to anti-NK-1.2 antiserum and C.
Biochemical characterization of Ia alloantigens in guinea pigs. II. Comparative peptide mapping of Ia antigens from B cells, T cells, and macrophages.
Authors: Lyons C R , Cook R G , Tucker T F , Uhr J W 
Published: December 2022

Abstract
Radioactive Ia.4 molecules were prepared from 3H- or 14C-labeled splenocytes, selected PEL, or bronchoalveolar macrophages (M phi). Studies in the accompanying paper indicated that incorporation into Ia.4 in these 3 populations is due to B cells, T cells, and macrophages, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to isolate the 58,000 m.w. form of Ia.4. The eluted molecule was then reduced, and the resultant alpha and beta subunits were isolated by a second separation on SDS-PAGE. Alpha (or beta) chains from 1 population labeled with 3H-amino acids was mixed with alpha (or beta) chains obtained from a population representing a different cell type that was labeled with 14C-amino acids and the mixture was digested with trypsin. Double-label (3H/14C) comparative peptide mapping was performed using high-pressure liquid chromatography to separate the peptides. Eighteen to 20 peaks of radioactivity were resolved from alpha chains, and 12 to 15 from beta chains. No reproducible differences were observed when comparing alpha or beta chains of T cells and macrophages, or those of B cells and macrophages. These results indicate that the primary structure of Ia.4 molecules is identical on the 3 cell types in question. The implications of having a T cell bearing the same Ia that it recognized on a macrophage in conjunction with antigen is discussed.
Resistance to immune cytolysis induced by 4NQO and MNNG: a possible mechanism involved in chemical carcinogenicity.
Authors: Okada H , Tanaka H , Cyong J C 
Published: December 2022

Abstract
L1210 cells were cultured for 20 hr in the presence of 4NQO or MNNG. Both agents rendered L1210 cells resistant to immune cytolysis by rabbit antibody and guinea pig complement. This resistance to immune cytolysis was not due to a loss or a distribution change of antigenic determinants to rabbit antibody, since the treated cells retained the capacity to consume guinea pig C4 in the presence of rabbit antibody to the same extent as untreated L1210 cells. Because acyltransferase activity to incorporate free fatty acids into phospholipids and neutral lipids of L1210 cells increased after the 4NQO and MNNG treatments, it was suggested that there might be a close relationship between the increased resistance of L1210 cells to immune cytolysis and the increase in their acyltransferase activity.