bluuebunny/crossref_metadata_2025 huggingface dataset:
Polyclonal activation of human B lymphocytes by Fc fragments. I. Characterization of the cellular requirements for Fc fragment-mediated polyclonal antibody secretion by human peripheral blood B lymphocytes.
Authors: Morgan E L , Weigle W O
Published: June 2004

Fc fragments derived from human immunoglobulin were found to be capable of inducing both a proliferative and polyclonal antibody response in human peripheral blood lymphocyte cultures. The cell population proliferating in response to Fc fragments belongs to the B cell lineage. Expression of polyclonal antibody formation requires the presence of both adherent monocytes and T cells. The role of the monocyte is to enzymatically cleave the Fc fragment into 19,000 mol wt Fc subfragments that are then able to induce polyclonal antibody secretion. Stimulation of polyclonal antibody production by Fc subfragments occurs in the absence of adherent monocytes but still requires the presence of T cells.
Analysis of T cell function in autoimmune murine strains. Defects in production and responsiveness to interleukin 2.
Authors: Altman A , Theofilopoulos A N , Weiner R , Katz D H , Dixon F J
Published: June 2004

In the studies reported here, we have analyzed the production and consumption of T cell growth factor, more recently termed interleukin 2 (IL-2), as well as some cell-mediated immune functions, in murine strains [MRL, BXSB, NZB, and (NZB x NZWF1] manifesting systemic lupus erythematosus (SLE)-like syndromes. Young (4-6 wk) or old (4-8 mo) autoimmune or normal mice were studied and compared with regard to the following T cell functions in vitro after stimulation with concanavalin A (Con A): (a) mitogenic response; (b) IL-2 levels in culture supernates; and (c) the ability to respond to and adsorb IL-2. In addition, proliferative activity in the allogeneic mixed leukocyte culture and frequency of alloreactive cytotoxic T lymphocyte precursors (CTLp) were analyzed in some of these strains. Reduced Con A-induced mitogenic responses and IL-2 production appeared at 3-6 wk of age in the early, severe SLE developing strains MRL-Mp-lpr/lpr (MRL/l) and male BXSB and progressed thereafter. Similar defects appeared at a later stage in MRL/Mp-+/+ and (NZB x NZW)F1 hybrid mice, which develop late disease. Detailed analysis of cells from the enlarged lymph nodes and spleens of older MRL/l mice demonstrated that such cells: (a) responded poorly to Con A or allogeneic stimulator cells, even in the presence of exogenous IL-2; (b) did not suppress IL-2 production by normal spleen cells; (c) were relatively incapable of adsorbing or inactivating IL-2; and (d) had a markedly reduced anti-H-2b CTLp frequency in the mesenteric lymph nodes but a normal one in spleen. These results indicate that the proliferating Thy-1.2+, Lyt-1+ T cells in MRL/l mice are defective in their responses to mitogenic stimuli, in IL-2 production, and in expression of acceptor sites for IL-2. The relevance of these defects to the MRL/l disease as well as to the role of IL-2 in autoimmunity in general remains to be determined.
Characteristics of Epstein-Barr virus activation of human B lymphocytes.
Authors: Bird A G , Britton S , Ernberg I , Nilsson K
Published: June 2004

Epstein-Barr virus (EBV) will infect at least every third cell if exposed in vitro to an extensively purified B cell population from human peripheral blood. About 10% of such infected cells will be driven into immunoglobulin synthesis and secretion, as judged by the indirect protein A plaque assay. The appearance of EB nuclear antigen, de novo DNA synthesis, and immunoglobulin secretion are linked phenomena accompanying infection as judged by viral dilution experiments, which yield kinetics of a one-hit order. Induction of immunoglobulin secretion in B cells by EBV requires de novo synthesis of DNA, and consequently, nontransforming EBV (P3HR1) will not induce immunoglobulin secretion and will also specifically block such induction from subsequently added EBV. The termination of immunoglobulin induction by EBV in short-term cultures appears to be T cell dependent.
In vitro generation of human cytotoxic lymphocytes by virus. Viral glycoproteins induce nonspecific cell-mediated cytotoxicity without release of interferon.
Authors: Casali P , Sissons J G , Buchmeier M J , Oldstone M B
Published: June 2004

Purified hemagglutinin and fusion glycoproteins of measles virus either in soluble form or inserted in artifical membranes bind to human peripheral blood lymphocytes and induce cell-mediated cytotoxicity (CMC) in a dose-response fashion. Both autologous and heterologous noninfected target cells are lysed in vitro. The expression of CMC is not inhibited by anti-measles virus antibody added to lymphocytes previously exposed to viral glycoproteins. THe killer lymphocytes are Fc receptor positive, both erythrocyte-rosetting and non-erythrocyte-rosetting, as assessed by both positive and negative selection experiments. The induction of nonspecific CMC by viral glycoproteins either in the soluble state or inserted into artificial membranes could be segregated from the CMC associated with whole virions. First, on kinetics studies, purified viral glycoproteins induced CMC more rapidly than did whole virus. Second, viral glycoprotein-produced response occurred in the absence of detectable release of interferon into the culture medium, whereas CMC activity due to whole virions was associated with interferon release. The fact that purified measles virus glycoproteins integrated into artificial membrane bilayers were as efficient as their soluble counterparts in inducing CMC suggests that the hydrophobic portion of the glycoproteins was not involved in the induction and expression of the lytic activity. Purified glycoproteins from lymphocytic choriomeningitis virus behave similarly, although this virus is unrelated to measles virus. It is inferred that interferon-independent CMC induced by viral glycoproteins might account for some of the biological reactions occurring early in the control of a viral infection.
Immune complex-induced human monocyte procoagulant activity. I. a rapid unidirectional lymphocyte-instructed pathway.
Authors: Schwartz B S , Edgington T S
Published: June 2004

It has previously been described that soluble antigen:antibody complexes in antigen excess can induce an increase in the procoagulant activity of human peripheral blood mononuclear cells. It has been proposed that this response may explain the presence of fibrin in immune complex-mediated tissue lesions. In the present study we define cellular participants and their roles in the procoagulant response to soluble immune complexes. Monocytes were shown by cell fractionation and by a direct cytologic assay to be the cell of origin of the procoagulant activity; and virtually all monocytes were able to participate in the response. Monocytes, however, required the presence of lymphocytes to respond. The procoagulant response required cell cooperation, and this collaborative interaction between lymphocytes and monocytes appeared to be unidirectional. Lymphocytes once triggered by immune complexes induced monocytes to synthesize the procoagulant product. Intact viable lymphocytes were required to present instructions to monocytes; no soluble mediator could be found to subserve this function. Indeed, all that appeared necessary to induce monocytes to produce procoagulant activity was an encounter with lymphocytes that had previously been in contact with soluble immune complexes. The optimum cellular ratio for this interaction was four lymphocytes per monocyte, about half the ratio in peripheral blood. The procoagulant response was rapid, reaching a maximum within 6 h after exposure to antigen:antibody complexes. The procoagulant activity was consistent with tissue factor because Factors VII and X and prothrombin were required for clotting of fibrinogen. WE propose that this pathway differs from a number of others involving cells of the immune system. Elucidation of the pathway may clarify the role of this lymphocyte-instructed monocyte response in the Shwartzman phenomenon and other thrombohemorrhagic events associated with immune cell function and the formation of immune complexes.
Monoclonal antibody to an IgD allotype induces a new type of allotype suppression in the mouse.
Authors: Tokuhisa T , Gadus F T , Herzenberg L A , Herzenberg L A
Published: June 2004

Studies presented here show that perinatal exposure to anti-IgD allotype antibodies induces a persistant IgG-allotype suppression in the mouse that differs markedly from either the short-term or chronic allotype suppressions induced by antibodies to IgG or IgM allotypes. This novel form of allotype suppression induced by injecting neonatal BALB/c x SJL mice with monoclonal antibody to the paternal Igh-5b (IgD) allotype drastically reduces paternal allotype production during the first 6 mo of the affected animal's life and simultaneously stimulates compensatory production of maternal allotype IgG. In addition, it interferes with the development of B cells carrying the paternal IgD allotype and impairs the development of memory B cells destined to give rise to paternal allotype IgG-producing cells. Thus, its properties make it more like allotype suppression as described in the rabbit than like the known forms of allotype suppression in the mouse. As shown here, Igh-5b-bearing (5b+) B cells are completely depleted from the neonate after anti-5b exposure and only gradually appear as the animal ages. The recovery of the 5b+ population to near normal size (by approximately 14 wk of age) substantially preceeds recovery of the ability to generate normal-size memory B cell populations. Paternal allotype levels in serum remain well below normal until the anti-5b-exposed animals reach approximately 6 mo of age and then climb rapidly, finally stabilizing at levels comparable to levels in controls of the same age. The elevated maternal allotype levels characteristic of the suppression period began falling somewhat earlier and are clearly stabilized within the normal range in 6-mo-old animals. Thus, perinatal exposure to anti-5b compromises B cell development and IgG production throughout early adulthood but has little apparent effect in older animals. Perinatal exposure to antibody to the paternal IgG2a allotype (Igh-1b) or IgM allotype (Igh-6b), in contrast, induces a chronic allotype suppression that has relatively little affect on IgG production in young adults but severely suppresses allotype production in older animals. Furthermore, this type of (chronic) suppression does not influence maternal allotype production and does not interfere with memory B cell development. These differences, illustrated here by data from parallel sets of animals exposed either toi anti-5b or anti-1b, raise a series of intriguing questions concerning the mechanisms regulating B cell development and expression and the nature of the neonatal (B) cell populations with which the suppression-inducing antibodies react.
Very rapid decay of mature B lymphocytes in the spleen.
Authors: de Freitas A A , Coutinho A
Published: June 2004

To determine the persistence of immunocompetent B lymphocytes at the periphery, regardless of cell division, we have followed the decay of lipopolysaccharide (LPS)-reactive B cells in LPS-nonresponder, histocompatible hosts. Both the numbers of transferred cells and of those persisting in the recipients could be determine with precision by limiting dilution analysis of the various cell populations. Decay rates of 50% per day were determined. Because we can exclude immune elimination of donor cells and the numbers of transferred cells were too low to result in gross alterations of the physiologic turnover rates, we conclude that the majority of LPS-reactive B lymphocytes and a large part of the whole B cell compartment show this astonishingly high rate of decay. The method introduced here might prove useful in a variety of clonal assays, as it can detect cells present at a very low frequency.
Thrombin-induced platelet membrane glycoprotein IIb and IIIa complex formation. An electron microscope study.
Authors: Polley M J , Leung L L , Clark F Y , Nachman R L
Published: June 2004

The topographic relationships of platelet membrane glycoprotein IIb and glycoprotein IIIa have been studied in stimulated and unstimulated human platelets using immunoelectron microscopy. An indirect approach with ferritin-conjugated goat anti-rabbit gamma-globulin was used to localize the rabbit antibody to glycoprotein IIIa. The second ultrastructural label was keyhole limpet hemocyanin conjugated directly to antibody to glycoprotein IIb. Using the double labels, it was demonstrated that glycoprotein IIb and glycoprotein IIIa were distributed randomly in the unstimulated platelet membrane. After platelet stimulation with thrombin, large clusters of glycoprotein IIb-glycoprotein IIIa complexes were formed. No complex formation between glycoprotein Ib and glycoprotein IIb was observed in control experiments. These observations suggest that thrombin stimulation initiates the specific glycoprotein IIb-glycoprotein IIIa macromolecular complex formation on the platelet surface, which may act as the active fibrinogen-binding site required for normal platelet aggregation.
Induction of lymphoid cell chimerism in noninbred, histocompatible rabbits. A new model for studying allotype suppression in the rabbit.
Authors: Adler L T , Adler F L , Cohen C , Tissot R G
Published: June 2004

Noninbred rabbits, matched with regard to the major histocompatibility complex (RLA-A and RLA-D loci) but mismatched for Ig allotypes, served as donors (adult) and recipients (newborn) of lymphoid cells. Lasting chimerism regularly followed the transfer of 1 x 10(8)-3 x 10(8) spleen, lymph node, or bone marrow cells, as indicated by the continued production of Ig with allotypic determinants of both donor and recipient. Typically, Ig of donor allotype accounted for 25-50% of total allotypic Ig at 4 wk of age and the amount of donor Ig produced remained stable for up to 20 mo. Total allotypic Ig levels remained normal in the chimeric rabbits. "Chimeric drift" or a gradual diminution of donor products over a period of several months, occurred in some individuals. Transfer of lymphoid cells from allotype-suppressed adult donors to newborns of appropriate allotypes did not result in specific suppression of the target allotype in the recipients. Other experiments showed that lymphoid cells from suppressed donors adoptively transferred to histocompatible recipients continued to synthesize Ig of the nonsuppressed type only. The suitability of using an outbred population of histocompatible but allotype-mismatched rabbits for analyzing allotype suppression and other immunoregulatory phenomena is demonstrated by the results presented here.
Role of the major histocompatibility complex in T cell activation of B cell subpopulations. Major histocompatibility complex-restricted and -unrestricted B cell responses are mediated by distinct B cell subpopulations
Authors: Asano Y , Singer A , Hodes RJ
Published: June 2004

The present study has evaluated the identity of the B cell subpopulations participating in T dependent antibody responses that differ in their requirements for major histocompatibility complex-restricted T cell recognition. In vitro responses of keyhole limpet hemocyanin (KLH)-primed T cells and trinitrophenyl (TNP)-primed B cells were studied to both low and high concentrations of the antigen TNP-KLH. It was first demonstrated that for responses to low concentrations of TNP-KLH, (A × B)F(1) {arrow} parent(A) chimeric helper T cells were restricted in their ability to recognize parent(A) but not parent(B) H-2 determinants expressed by both B cells and antigen-presenting cells (APC). In contrast, at higher antigen concentrations, helper T cells were not restricted in their interaction with B cells.

It was then determined whether these observed differences in T cell recognition resulted from the activation of distinct B cell subpopulations with different activation requirements. At low concentrations of TNP-KLH it was demonstrated that Lyb-5(-) B cells were activated, and that it was thus the activation of the Lyb-5(-) subpopulation that required T cell recognition of B cell H-2 under these conditions. In contrast, responses to high concentration of antigen required the participation of Lyb-5(+) B cells, and these Lyb-5(+) B cells were activated by a pathway that required H-2- restricted T cell interaction with APC, but not with B cells.

The findings presented here have demonstrated that Lyb-5(-) and Lyb-5(+) B cells constitute B cell subpopulations that differ significantly in their activation requirements for T cell-dependent antibody responses to TNP-KLH. In so doing, these findings have established that the function of genetic restrictions in immune response regulation is critically dependent upon the activation pathways employed by functionally distinct subpopulations of B, as well as T, lymphocytes.
Low-calorie diet selectively reduces expression of retroviral envelope glycoprotein gp70 in sera of NZB x NZW F1 hybrid mice.
Authors: Izui S , Fernandes G , Hara I , McConahey P J , Jensen F C , Dixon F J , Good R A
Published: June 2004

The effect of dietary restriction on the expression of retroviral envelope glycoprotein, gp70, and the formation of gp70-anti gp70 immune complexes was investigated in lupus-prone NZB x NZW F1 hybrid mice. Restricting total calorie intake from the usual 20 to only 10 calories per day after weaning markedly reduced serum levels of both free and antibody-complexed gp70, prevented renal disease, and increased the life spans of these mice. The reduction in serum gp70 was evident after only 2 wk of feeding these animals the low-calorie diet, and the concentration remained virtually unchanged throughout the course of 10 mon experimentation. However, serum concentrations of the major structural protein, p30, of endogenous retroviruses were not altered by restricting calories. Amounts of the serum glycoprotein, haptoglobin, decreased parallel to those of gp70 but amounts of albumin did not. These results suggest that the expression of gp70 in serum is controlled independently of the production of complete viral particles, and regulated by a mechanism similar to that for other serum glycoproteins, such as haptoglobin.
Induction of monocyte procoagulant activity by murine hepatitis virus type 3 parallels disease susceptibility in mice.
Authors: Levy G A , Leibowitz J L , Edgington T S
Published: June 2004

The in vitro induction of procoagulant activity (PCA) in murine peripheral blood mononuclear cells (PBM) by murine hepatitis virus type 3 (MHV-3) correlates with the disease susceptibility in three strains of mice. PBM from BALB/c mice, a strain in which MHV-3 infection results in fatal acute fulminant hepatitis, responds to the virus with a robust PCA response, whereas PBM from C3H/St mice, a strain which develops mild acute hepatitis followed by chronic hepatitis, only exhibit a modest PCA response. In contrast, PBM from A/J mice, a strain fully resistant to MHV-3, generate no increase in PCA above control levels. The induction phase of MHV-3 PCA is rapid, with an increase within 1-1.5 h, with maximum activity at 18h, and it precedes MHV-3 replication in either 17 CL1 cells, a fully permissive cell line, or in monocytes from these strains of mice. The PCA response of BALB/c PBM exceeds the response to any other known stimulus. No induction occurs upon direct stimulation of monocytes by MHV-3, but in the presence of lymphocyte collaboration, the PCA response is observed first at a lymphocyte:monocyte ratio of 2:1 and reaches a maximum as the lymphocyte:monocyte ratio approaches 4:1. This response appears to provide a functional marker for susceptibility to MHV-3 infection in inbred strains of mice and could be important in the pathogenesis of MHV-3-induced disease.
Genetics of susceptibility for radiation-induced leukemia. Mapping of genes involved to chromosomes 1, 2, and 4, and implications for a viral etiology in the disease.
Authors: Meruelo D , Offer M , Flieger N
Published: June 2004

Susceptibility to radiation-induced leukemia in (A/J x B10)F2 mice is encoded for by genes in chromosomes 1, 2, and 4. The loci involved in chromosomes 1 and 4 are close to or similar to xenotropic virus inducibility locus on chromosome 1 and a locus-affecting expression of xenotropic MuLV envelope-related cell surface antigens. Radiation-induced leukemia-1 (Ril-1) on chromosome 2 plays an overriding influence in susceptibility to the disease. This locus might encode ecotropic viral-associated genetic information or might contain cellular sequences with oncogenic potential. These findings are of interest in view of the importance of recombinant viruses to leukemogenesis. Furthermore, it is intriguing that Ril-1 is located in a chromosomal site rich in thymus differentiation-specific loci. An explanation for tissue-specific activation of endogenous viruses is that activation of the virus in question is dependent on differentiation-specific steps.
Clonal analysis of F1 hybrid helper T cells. I-A subregion-encoded hybrid determinants restrict the activity of keyhole limpet hemocyanin-specific helper T cells.
Authors: Sproviero J F , Imperiale M J , Zauderer M
Published: June 2004

Clonal expansion of isolated precursors to helper T cells was induced in limiting dilution cultures of keyhole limpet hemocyanin (KLH)-primed F1 hybrid lymph node cells. Progeny of each isolated precursor was tested for helper activity by transfer to independent cultures with hapten-primed B cells of either parental or F1 hybrid origin. The major histocompatibility complex (MHC) restriction specificity of each F1 hybrid helper T clone was determined. To assess the contribution of I-A and I-E subregion-encoded genes to the expression of these restriction elements, helper T cell cultures derived from F1 hybrids between strains with recombinant H-2 haplotypes were analyzed. Parental and unique F1 hybrid MHC determinants that are encoded entirely within the I-A subregion were found to restrict the activity of KLH-specific helper T cells.
Anti-idiotypes to monoclonal anti-H-2 antibodies. II. Expression of anti-H-2Kk idiotypes on antibodies induced by anti-idiotype or H-2Kk antigen.
Authors: Bluestone J A , Epstein S L , Ozato K , Sharrow S O , Sachs D H
Published: June 2004

Anti-idiotypic antibodies were prepared against two monoclonal anti-H-2Kk antibodies, 11-4.1 and 3-83P. These reagents were used to examine idiotype (Id) expression on anti-H-2Kk antibodies induced by the in vivo administration of the anti-idiotypic antibodies and/or H-2Kk antigen. Treatment of BALB/c mice with anti-Id induced both antigen-binding and nonantigen-binding Id-positive molecules in the absence of antigen. The level of production of anti-Id-induced Id (Id') has been shown to be linked to VH genes using allotype congenic mice and backcross analyses. The idiotypes expressed on the Id' induced in anti-Id-treated mice were closely related or identical to those of the original monoclonal anti-H-2Kk antibody. However, the idiotopes were present on immunoglobulins of different subclasses and in some cases were not all expressed on the same molecules, as reflected by differences in their antigen specificities and isoelectric focusing patterns. In vivo administration of anti-Id had a marked influence on the subsequent humoral response to immunization with H-2 antigen.
The vascular bed as the primary target in the destruction of skin grafts by antiserum. II. Loss of sensitivity to antiserum in long-term xenografts of skin.
Authors: Jooste S V , Colvin R B , Winn H J
Published: June 2004

Rat skin that survives for long periods of time on immunosuppressed mice becomes resistant to anti-graft serum and remains so for as long as it survives. When long-standing grafts are removed and placed on new immunosuppressed mice, they remain resistant to antiserum for as long as they survive. The acquired resistance to antiserum seems, therefore, to be due to changes in the grafts rather than to changes in their hosts. Furthermore, it was found that the acquisition of resistance is correlated with replacement of graft endothelium by host cells, as demonstrated by the use of immunofluorescent techniques in conjunction with mouse anti-rat serum and rat anti-mouse serum. Evidently, humoral antibodies are able to cause acute damage to skin grafts, and presumably to grafts to other organized tissues, only if they react with antigens of graft endothelium. Long-term grafts that are retransplanted to their original donors or to rats syngeneic with those donors are in most cases rejected, whereas 14-d-old grafts similarly regrafted are in no case rejected. Apparently, the responses of the secondary recipients to the mouse endothelial antigens in long-term grafts lead to destruction of the entire grafts. When long-standing rat skin xenografts are removed and placed on untreated mice syngeneic with the primary hosts, they are in every case rejected, although they survive slightly longer than skin taken directly from rat donors. Rejection is accompanied by a mononuclear infiltrate and is qualitatively indistinguishable from the rejection of freshly prepared rat skin. Clearly, sensitized cells are more efficient than humoral antibody in destroying grafted tissues.
A common idiotype on SJL and C57BL/6 anti-(4-hydroxy-3-nitrophenyl) acetyl antibodies and its relationship with lambda chain production.
Authors: Ju S T , Karjalainen K , Dorf M E
Published: June 2004

Hybridoma cell lines secreting antibodies specific to (3-nitro-4-hydroxyphenyl) acetyl (NP) were generated by fusion of NP-immunized SJL spleen cells with the SP2/0 cell line. One hybridoma (N-hybridoma) anti-NP antibody (mu, lambda2) was found to partially inhibit (35-40%) the binding of the predominant idiotype in primary C57BL/6 anti-NP antibodies (NPb). Iodinated hybridoma antibody could be completely bound with anti-idiotypic antiserum made against either specifically purified C57BL/6 anti-NP antibodies, SJL anti-NP antibodies, or N-hybridoma antibody. The idiotypic specificities defined with anti-idiotypic antiserum made against N-hybridoma antibody were termed NP-1 idiotype. Strain distribution and genetic mapping studies indicate that the gene(s) controlling the production of NP-1 idiotype is closely associated with Igh-1b and Igh-1e alleles and mapped within the same chromosomal segment that controls the synthesis of NPb idiotype. However, unlike NPb idiotype, the expression of NP-1 idiotype is not influenced by the gene(s) that control lambda1 chain synthesis. Thus, SJL mice that produce low or undetectable levels of NPb idiotype due to a defect in lambda1 chain production express high levels of NP-1 idiotype. Specifically purified C57BL/6 and SJL anti-NP antibodies fully express NP-1 idiotype, the level of which correlates with the level of lambda2 chain-bearing molecules. Nonetheless, further experiments indicate that lambda1-bearing anti-NP antibodies can express extremely weak NP-1 idiotypic cross-reactivity.
Expression of an idiotype (Id-460) during in vivo anti-dinitrophenyl antibody responses. II. Transient idiotypic dominance.
Authors: Dzierzak E A , Rosenstein R W , Janeway C A
Published: June 2004

After immunization of mice with 2,4-dinitrophenyl-ovalbumin (DNP-OVA), it was shown previously that strains having Igh-Va genes and able to express light chains of the Vk1 group produce high levels of anti-DNP antibody bearing an idiotype (Id-460) associated with the combining site of the BALB/c DNP-binding myeloma protein MOPC 460. Expression of Id-460 in serum is transient; Id-460 levels peak early in the response and are regulated independently of total anti-DNP antibody. In this paper, the transient dominance of Id-460 expression has been confirmed at the cellular level by inhibition of splenic anti-DNP plaque-forming cells (PFC) with rabbit anti-Id-460 antiserum. Id-460+ PFC can account for 52-91% of anti-DNP PFC early after secondary challenge with DNP-OVA. Furthermore, Id-460 is represented at these high levels in IgM, IgG, and IgG1, and IgG2a, the three isotypes tested in the PFC assay, as well as in IgE, as tested by passive cutaneous anaphylaxis. Thus, there is no preferential association of Id-460 with a given isotype. We conclude from these studies that Id-460 is a dominant idiotype in the anti-DNP antibody response of BALB/c mice to DNP-OVA. This dominance is expressed transiently and is independent of isotype. A further conclusion from these studies is that regulation of isotype expression is independent of the regulation of idiotype expression in this system. We would suggest that regulation of Id-460 expression involves Ig-dependent helper T cells specific for Id-460 that induce Id-460+ B cells and also activate suppressor T cells, both events occurring via idiotype-anti-idiotype interactions.
Failure to cleave measles virus fusion protein in lymphoid cells. A possible mechanism for viral persistence in lymphocytes
Authors: Fujinami RS , Oldstone MBA
Published: June 2004

The host-directed cleavage of measles virus fusion protein on infected lymphoid cells was studied to understand the mechanism of viral persistence in lymphoid cells in vivo. Several lymphoblastoid cell lines were infected with measles virus, and the viral glycoproteins expressed on the cell's surface were radiolabeled and analyzed for cleavage of fusion (F(0)) to F(1) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Daudi and Ramos lymphoblastoid cells were deficient in their ability to cleave measles virus fusion protein and correspondingly produced low titers of infectious measles virus, Daudi cells being more defective than Ramos cells. In contrast, other lymphoblastoid cells studied, Victor, Raji, Wi-L2, RPMI 8866, and Seraphine, cleaved the fusion polypeptide and made significantly more infectious virus. Despite their defect in cleaving F protein, Daudi cells were able to assemble and release (noninfectious) measles virus particles into the fluid phase. The deficit in Daudi cells was corrected by fusing infected Daudi cells with cleavage-competent cells such as Victor or Raji. Furthermore, the cleavage event performed by competent cells could be mimicked at the plasma membrane by treating infected Daudi cells with trypsin, implicating the role of a plasma membrane enzyme in cleaving F(0) to F(1) during measles virus infection. Hence, lymphoid cells deficient in the plasma membrane enzyme required to cleave F protein are permissive for measles virus, maintain viral gene products, produce mostly noninfectious virus, and fail to place the biologic activity F(1) protein on their surfaces.
Long-term culture and cloning of nontransformed human B lymphocytes.
Authors: Sredni B , Sieckmann D G , Kumagai S , House S , Green I , Paul W E
Published: June 2004

B lymphocyte-enriched cell populations cultured with mitogens in initial suspension cultures formed colonies in soft agar when the same mitogenic agent was present in the lower layer of a two-layer soft agar system. Colony formation depended upon the presence of T cells in the initial culture, and was optimal after an initial 72-h culture with phytohemagglutinin (PHA; 12.5 microliters/ml), pokeweed mitogen (PWM; 2.5 micrograms/ml), or protein A (10 micrograms/ml). The colonies could be picked from the agar and propagated by feeding every 3 d with medium supplemented with a growth factor-containing tissue culture supernate. The growth factor-containing supernate was prepared by stimulating pools of human peripheral blood mononuclear cells for 72 h with PHA or PWM. The lines propagated in this manner were membrane Ig+, lacked sheep erythrocyte rosette-forming ability, and did not ingest latex. They lacked the Epstein-Barr nuclear antigen (EBNA) and had 46 chromosomes. Such lines have been propagated for over 1 yr. One line (BL1) was subjected to limiting dilution cloning and a line, BL1.1, was prepared that contained 96% lambda-bearing cells and no kappa-bearing cells. This line was also EBNA negative. This procedure can thus be used to prepare and clone long-term lines of nontransformed human B lymphocytes.
Molecular complexity of leukocyte surface glycoproteins related to the macrophage differentiation antigen Mac-1.
Authors: Trowbridge I S , Omary M B
Published: June 2004

Monoclonal antibodies have been obtained that react with the murine leukocyte surface glycoproteins bearing the macrophage differentiation antigen Mac-1. Structural and antigenic analysis shows that related glycoproteins are found on other murine hematopoietic cell types. The data not only illustrate the complexity of cell surface structures that can be detected by means of monoclonal antibodies, but also raise questions as to the functional significance of this family of molecules within the hematopoietic system.
Regulation of immune responses by I-J gene products. I. Production and characterization of anti-I-J monoclonal antibodies.
Authors: Waltenbaugh C
Published: June 2004

Using a novel, two-step functional screening procedure, we have isolated hybridoma B cell lines secreting monoclonal antibodies directed against gene products of the I-Jb and I-Jk subregions of the mouse H-2 complex. These monoclonal antibodies act in vitro by allowing nonresponder spleen cells to respond to normally suppressive quantities of poly(Glu50Tyr50) (GT) (WF8 series of anti-I-Jk monoclonal antibodies) or to suboptimal concentration of poly(Glu60Ala30Tyr10) (WF9 series of anti-I-Jb monoclonal antibodies). Some of the culture supernates that show augmenting activity bind GT-specific T cell-derived suppressor factor (GT-TsF), indicating that some monoclonal antiantibodies display a nonspecific enhancing effect, or, more likely, that anti-I-J monoclonal antibodies have been produced against I-J determinants not found on TsF. It is this last possibility that is most intriguing and that might serve as a means for exploring the heterogeneity of the I-J subregion. It is also possible that some of our monoclonal anti-I-J antibodies might detect antigenic determinants selectively expressed on suppressor T cells, helper T cells, and/or macrophages. In addition, we have demonstrated that monoclonal anti-I-J antibodies should be useful in the biochemical characterization and purification of a monoclonal GT-TsF. These haplotype-specific anti-I-J monoclonal antibodies should prove to be powerful tools for future studies exploring the role of I-J gene products in the regulation of specific immune responses.
Occurrence of an incomplete C8 molecule in homozygous C8 deficiency in man.
Authors: Tschopp J , Esser A F , Spira T J , Müller-Eberhard H J
Published: June 2004

Sera from unrelated individuals with recurrent Neisserial infections lacked C8 hemolytic activity, but contained a protein that is antigenically related to C8. Immunochemical analysis revealed complete identity of the C8-related protein of all three sera and a marked antigenic deficiency compared with normal C8. The C8-related protein was isolated from serum by adsorption to immobilized anti-C8 IgG, elution with 3 M guanidine, and subsequent gel filtration. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, the abnormal protein resembled the alpha-gamma subunit of normal C8 with respect to mobility and its ability to be cleaved upon reduction into the alpha and gamma chains. The beta chain present in normal C8 was absent. Sedimentation equilibrium analysis indicated a molecular weight of 86,000 for the abnormal C8 protein, which is identical to that of the alpha-gamma subunit of normal C8. Amino acid analysis revealed no significant difference between the abnormal C8 and normal alpha-gamma. Unlike normal C8, the abnormal protein did not bind to EAC1-7 or to SC5b-7; however, upon addition to the deficient serum of beta chain isolated from normal C8, hemolytic activity was restored and formation of SC5b-9 occurred. We concluded that the dysfunctional C8 protein in the three individuals' serum is identical to the alpha-gamma subunit of normal C8 and that this form of C8 deficiency is distinct from the C8 deficiencies previously reported in which the entire three-chain protein is lacking.
B cell helper factors. I. Requirement for both interleukin 2 and another 40,000 mol wt factor.
Authors: Leibson H J , Marrack P , Kappler J W
Published: June 2004

A helper factor(s) distinct from interleukin 2 (IL-2) was shown to be present in the concanavalin A-stimulated supernatant of normal mouse spleen cells (normal Con A Sn). Spleen cells thoroughly depleted of T cells required both IL-2 and this factor to produce antibody-secreting cells in response to sheep erythrocytes, although in the presence of IL-2 and a few T cells the requirement for the factor was less apparent. The factor had an apparent approximately 40,000 mol wt. The factor was found in normal Con A Sn that had been depleted of IL-2 by absorption with IL-2-dependent T cells and was absent from Con A-stimulated supernatants of the IL-2-producing T cell hybridoma, FS6-14.13. These results indicate that multiple helper factors control the B cell response to antigen and that IL-2, in addition to its T cell growth promoting activity, plays a direct role in B cell responses.
Monoclonal ant-idiotypic antibodies reactive with a highly conserved determinant on A/J serum anti-para-azophenylarsonate antibodies.
Authors: Nelles M J , Gill-Pazaris L A , Nisonoff A
Published: June 2004

Previous reports have shown the A/J anti-para-azophenylarsonate (anti-Ar) antibodies that share a major cross-reactive idiotype (CRI) comprise a family of closely related but nonidentical molecules. Serological studies with CRI+ monoclonal anti-Ar antibodies have suggested the presence of a conserved idiotypic determinant within the family. The present study utilized monoclonal ant-idiotypic determinant within the family. The present study utilized monoclonal anti-idiotypic antibodies to define further the nature of the conserved idiotypic determinant. It was found that 8 of 10 CRI+ monoclonal antibodies possess an idiotypic determinant reactive with each of three monoclonal anti-idiotypic antibodies. In addition, approximately 60% of CRI+ serum anti-Ar antibodies reacted with one of the monoclonal anti-idiotypic preparations. The monoclonal anti-idiotypic antibodies react with an idiotope in the region of the hapten-binding site, as indicated by the ability of free haptens to inhibit idiotype-anti-idiotype interactions. Finally, two of three monoclonal anti-idiotypic antibodies suppressed the subsequent production of CRE+ serum anti-Ar antibodies when administered before antigen, without significantly affecting the total anti-Ar response.
Renal localization of the membrane attack complex in systemic lupus erythematosus nephritis.
Authors: Biesecker G , Katz S , Koffler D
Published: June 2004

The membrane attack complex (MAC) of the complement system was localized in both glomeruli and peritubular regions of 22 kidneys manifesting systemic lupus erythematosus (SLE) nephritis. A similar distribution was observed for immune complex markers (IgG, Clq, and C3) and MAC in glomeruli, although the deposits of MAC were more discrete and showed lesser immunofluorescence staining intensity compared with immunoglobulins and complement components. In contrast, peritubular immune complexes were present in only 7 out of 22 kidneys, involved comparatively small clusters of tubules, exhibited weaker immunofluorescence staining than MAC, and failed to correlate with interstitial foci of inflammation. Granular or irregular, linear aggregates of the MAC were observed at the periphery of larger groups of tubules contiguous to areas of interstitial inflammation. Comparable amounts of IgG, Clq, C3, and MAC were present in blood vessel walls in areas of fibrinoid necrosis. These data suggest that the MAC is a direct mediator of tissue injury occurring in renal glomeruli, tubules, and blood vessels. The discordance between immune complexes and MAC localized in the peritubular region, but not in glomeruli or blood vessels, raises the possibility that both immune complexes and nonimmune agents, such as bacterial antigens, may activate the classical or alternative complement pathways and thereby play a role in the pathogenesis of tubulointerstitial lesions of SLE nephritis.
Two separate genes regulate self-Ia and carrier recognition in H-2-restricted helper factors secreted by hybridoma cells.
Authors: Lonai P , Bitton S , Savelkoul H F , Puri J , Hämmerling G J
Published: June 2004

H-2 heterologous T cell hybridomas were used to study the genetic control of dual, anti-nominal antigen and anti-self H-2 specificity of H-2 restricted T cell factors. Each of four hybridoma clones produced two helper factors. One was restricted for the Ia type of the normal T cell partner (H-2b), whereas the other was restricted for the ia type of the lymphoma partner (H-2k) of the somatic hybrid. This was shown by affinity separation on parental type spleen cells and on monoclonal anti-I-A-Sepharose. Both factors had carrier (chicken gamma globulin; CGG)-specific helper effect, and both bound to anti-VH-315-Sepharose. Because the lymphoma (BW-5147) partner could not contribute a CGG-specific locus, the H-2k-restricted, CGG-specific factor had to be the product of segregating anti-nominal and anti-self loci. This suggests that dual specificity is due to two independent loci and support the validity of dual recognition concepts. Anti-self specificity was associated with homologous Ia alloantigens in the individual factors. Therefore, Ia and anti-self might be linked. Implications of the major histocompatibility complex or VH nature of anti-self receptors and the relationship of T cell factors and receptors was discussed.
A monoclonal antibody that defines an idiotope with two subsites in galactan-binding myeloma proteins.
Authors: Pawlita M , Mushinski E , Feldmann R J , Potter M
Published: June 2004

An IgG1 monoclonal antibody HyX24-14 was derived from A/J mice that were immunized with the IgA XRPC24 (X24) galactan binding myeloma protein (GalBMP) of BALB/c origin by the Kohler-Milstein hybridoma technology. HyX24-14 specifically binds some but all GalBMP. Different patterns of binding using a panel of nine Gal BMP were found, depending upon the concentration of antibody and the antigenic target. From molecular models and amino acid sequence data, ti was proposed that the idiotope defined by HyX24-14 had two subsites, each of which appeared to be able to bind independently to the antibody.
Antigen recognition by cloned cytotoxic T lymphocytes follows rules predicted by the altered-self hypothesis.
Authors: Hünig T R , Bevan M J
Published: June 2004

Radiation chimeras prepared by injecting H-2 heterozygous F1 stem cells into lethally irradiated parental hosts show a marked, but not absolute, preference for host-type H-2 antigens in the H-2-restricted cytotoxic T lymphocyte (CTL) response to minor histocompatibility (minor H) antigens. We have selected for the anti-minor HCTL that are restricted to the parental H-2 type absent from the chimeric host and found that in two out of eight cases, such CTL lysed target cells of either parental H-2 type. From one of these CTL populations that lysed H-2d and H-2k target cells expressing BALB minor H antigens, clones were derived and further analyzed. The results showed that: (a) lysis of both H-2d and H-2k target cells was H-2 restricted; (b) H-2d restriction mapped to Dd, and H-2k restriction mapped to Kk; (c) testing against various H-2d and H-2k strains of different and partially overlapping minor H backgrounds as well as against the appropriate F1 crosses revealed that in Dd- and Kk-restricted killing, different minor H antigens were recognized. In a second system, a CTL population was selected from normal (H-2d x H-2k)F1 mice that was specific for H-2d plus minor H antigens and for H-2k plus trinitrophenylated bovine serum albumin. We interpret these findings in terms of the altered-self hypothesis: The association of one H-2 antigen with one conventional antigen X may be recognized by the same T cell receptor specific for the complex formed by a different H-2 antigen in association with a second conventional antigen Y. The implications of these observations for the influence of self H-2 on the generation of the T cell receptor repertoire are discussed.
Triggering of affinity-enriched B cells. Analysis of B cell stimulation by antigen-specific helper factor or lipopolysaccharide. I. Dissection into proliferative and differentiative signals.
Authors: Jaworski M A , Shiozawa C , Diener E
Published: June 2004

Proliferative and differentiative signals controlling the in vitro IgM response by unprimed, affinity-enriched B cells were studied using conditions under which as few as 2,000 B cells stimulated by antigen-specific, Ia-positive, allogeneically restricted, T cell-derived helper factor (Hf) or the polyclonal activator lipopolysaccharide (LPS) yielded on the average 400 antibody-forming cells (AFC) by direct plaque assay. Antigen alone induces neither B cell proliferation nor differentiation into AFC. Proliferation but not differentiation into AFC is induced when affinity-enriched B cells are cultured in the presence of Ag and Hf or LPS but in the absence of nonantigen-specific, radioresistant, accessory (A) cells. For the induction of a complete Hf- or LPS-mediated AFC response, cultures must be reconstituted with A cells or the secretory product(s) of these cells. The antigen-specific response depends strictly on the presence of the Hf specific for the relevant antigen, regardless of the cell cycle state of cooperating B cells. The differentiative signal from A cells is due, at least in part, to the presence of a Thy-1.2-bearing population of cells. In the case of the LPS-mediated, but not the Hf-mediated response. A cells can be substituted by using supernatant derived from an interleukin 2-secreting T lymphoma cell line (EL4). In the presence of histocompatible Hf and B cells, histoincompatible A cells can still cooperate in the immune response. However, the degree of allogeneic restriction between incompatible Hf and B cells is markedly increased if both B cells and A cells are incompatible with Hf.
Self recognition in allogeneic thymic chimeras. Self recognition by T helper cells from thymus-engrafted nude mice is restricted to the thymic H-2 haplotype.
Authors: Singer A , Hathcock K S , Hodes R J
Published: June 2004

To examine the possibility that the thymus determines the I region-restricted self-recognition repertoire expressed by T helper (TH) cells, thymic chimeras were constructed by transplanting allogeneic neonatal thymic lobes into congenitally athymic nude mice. Spleen TH cells from the thymic chimeras were themselves of nude host origin but only cooperated with B+ accessory cells of the thymic haplotype for primary in vitro responses to sheep erythrocytes and trinitrophenyl conjugate of keyhole limpet hemocyanin. Thus, these experiments demonstrate that the self-recognition repertoire expressed by TH cells is determined by the H-2 phenotype of the intrathymic environment in which the TH cells had differentiated.
Tthyd, a new thymocyte alloantigen linked to Igh-1. Implications for a switch mechanism for T cell antigen receptors.
Authors: Owen F L , Spurll G M , Panageas E
Published: June 2004

Tthyd is an alloantigen coded for by a gene(s) near the immunoglobulin locus on chromosome 12 in the mouse. This T cell-specific antigen may be the third member of a family of antigen receptors on T cells encoded by a cluster of genes in the IgT-C region. This antigen is preferentially expressed on thymocytes in contrast to Tindd or Tsud that are expressed on peripheral T cells. The hypothesis that T cell receptors undergo a switch in surface isotype upon maturation is discussed.