bluuebunny/crossref_metadata_2025 huggingface dataset:
Suppression of IgE antibodies to the (4‐hydroxy‐3‐iodo‐5‐nitrophenyl)acetyl (NIP) group and induction of NIP‐specific suppressor cells with NIP‐poly‐N‐vinylpyrrolidone conjugates
Authors: Lee Weng Y. , Sehon Alec H. , Von Specht Berndt U.
Published: February 2007

The capacity of (C57BL/6 × DBA/2)F1 mice to produce anti‐(4‐hydroxy‐3‐iodo‐5‐nitrophenyl)acetyl (NIP) IgE antibodies, as a result of immunization with 1 μg of NIP2‐ovalbumin (OA) in the presence of Al(OH)3, was specifically suppressed by treatment of mice, either before or after immunization, with tolerogenic conjugates consisting of the hapten coupled to poly‐N‐vinylpyrrolidone (PVP) with an average mol. wt. of 10000. The suppression was hapten‐specific, since it did not affect the immune response of the host to OA. The unresponsive state of the spleen cells of mice which had been tolerized with respect to NIP was maintained even after cell transfer into X‐irradiated, syngeneic recipients and was shown to be due to hapten‐specific suppressor cells. However, the splenic B cells of these mice did not possess any suppressive activity. The generation of an effective number of suppressor cells required between 1 and 2 days following the administration of the tolerogen. The suppressive effects observed on adoptive transfer could not be attributed to the carryover of the tolerogen, which might have been associated with the spleen cells of the donor mice, since the transfer of B cells of tolerized mice or of mice which had received 2 mg of the tolerogen 2‐24 h before cell transfer did not abrogate the capacity of spleen cells of immune mice to mount an anti‐NIP response. Hence, it may be concluded that NIP2‐PVP induced, in addition to a probable receptor blockade of B cells, a central inhibitory mechanism which led to the development of an effective number of suppressor cells within 1 to 2 days after administration of NIP2‐PVP.
Early precursors of B lymphocytes I. Rabbit/mouse species differences in the physical properties and surface phenotype of pre‐B cells, and in the maturation sequence of early B cells
Authors: McElroy Paul J. , Willcox Nicholas , Catty David
Published: February 2007

Cells that possess low levels of internal IgM (or μ chain), with none detectable on the surface, can be identified by immunofluorescence. These “pre‐B cells” in rabbits have been characterized and been compared with those of mice, in terms of their ontogeny, physical properties and surface phenotype — partly to reveal features that could be exploited in their purification. The timing of their appearance and their tissue distribution are, in principle, very similar, though they first appear 5‐7 days later in the rabbit than in the mouse. Thus, pre‐B cells could not be detected in rabbit fetal liver until days 17‐20 of gestation; however, their progenitors appeared to be present before that, since, in preliminary experiments, pre‐B cells (and subsequently B cells) were generated de novo in closed organ cultures initiated at earlier times.

In other respects, pre‐B cells are strikingly different in the two species. Rabbit pre‐B cells bear detectable surface Fc receptors, not found on these cells in the mouse, and they are almost uniformly large and low in density, whereas mouse pre‐B cells are much more heterogeneous and less readily purified. The evidence summarized here that the large pre‐B cells identified by immunofluorescence are equivalent to those detected by others in functional assays, amounts to a strong case for their precursor status. In the mouse, their immediate progeny seem to be small pre‐B cells which apparently already behave, in functional assays, like the newly developed B cells into which they can rapidly convert.

This heterogeneity seen in pre‐B cells in mice is apparent instead in the B cells of rabbit lymphopoietic tissues. These vary considerably, not only in size and density, but also in their membrane Ig staining intensity, whereas the B cells in mouse bone marrow are almost exclusively small lymphocytes. In view of their relatively high frequencies in fetal tissues, it is proposed that the conspicuous large, low‐density rabbit B cells are intermediates in the development of pre‐B cells into small B lymphocytes, and it is therefore concluded that surface Ig and Fc receptors both appear at relatively earlier stages in the rabbit than in the mouse. This conclusion could be tested by culturing these immature B cells after purifying them by exploiting their distinctive properties.
Early precursors of B lymphocytes II. Exploitation of the singular properties of rabbit pre‐B cells in their purification
Authors: Willcox Nicholas , McElroy Paul J. , Catty David
Published: February 2007

Rabbit pre‐B cells are almost uniformly large and low in density and bear a modest number of Fc receptors (McElroy, P. J., Willcox, N. and Catty, D., Eur. J. Immunol. 1981. 11: 76). A simple density gradient centrifugation procedure consistently and rapidly enriches them to 20‐35% frequencies. At the same time, it depletes them of most of the B cells, phagocytic and erythroid cells that are also common in bone marrow, and are of progressively higher densities. The low‐density fractions include 45‐55% of large blast‐like cells and have 35‐45% of cells with Fc receptors.

By isolating the large Fc receptor‐bearing cells from low‐density fractions of baby rabbit bone marrow on a fluorescence‐activated cell sorter, pre‐B cells were obtained at approximately 60% frequency and virtually uncontaminated by B cells (or plasma cells). This level of purity is perhaps adequate for the critical experiments necessary to establish the precursor status of pre‐B cells definitively, and it might also prove valuable for studying the mechanisms of the genetic rearrangements that occur in early B cell development.
The role of macrophages in the activation of T lymphocytes by concanavalin A II. Macrophage‐independent activation
Authors: Resch Klaus , Heckmann Beate , Schober Irmtraud , Bärlin Erich , Gemsa Diethard
Published: February 2007

Lymphocytes from the mesenteric lymph nodes of Lewis rats were depleted of macrophages by absorption for 60 min at 37°C on 0.1‐mm glass beads in the presence of 30% fetal calf serum. Lymphocytes which passed the column (total recovery 30‐50%) contained less than 0.2% macrophages, as assessed by neutral red ingestion or nonspecific esterase staining. At cell densities which allowed optimal proliferation of concanavalin A (Con A)‐stimulated, untreated lymphocytes (2 × 106 cells/ml), macrophage‐depleted lymphocytes were completely incapable of initiating DNA synthesis. The proliferative response to Con A was fully restored by adding back macrophages obtained from the peritoneal cavity. The help of macrophages was optimal at concentrations of 0.8 × 105 cells/ml, which corresponds to about 4% of lymphocytes. Restitution of the mitotic response of macrophage‐depleted lymphocytes was also achieved by raising cell densities to 5 × 106/ml. At this cell density, addition of macrophages was without any effect. Early events in lymphocyte activation, such as the increase of the incorporation of 14C‐oleate into membrane phospholipids after 4 h stimulation, was identical in the presence or absence of macrophages independent of the cell density ranging between 1 × 106 and 10 × 106 cells/ml. Similarly, the Con A‐stimulated early increase in the incorporation of [3H]uridine into RNA was indistinguishable in macrophage‐containing or ‐depleted lymphocytes. At low cell densities, only macrophage‐containing lymphocytes proceeded to increase RNA synthesis, until S‐phase, whereas in the absence of macrophages RNA synthesis approached background values after 40 h of Con A stimulation. Macrophage‐depleted lymphocytes, too, proceeded with an increase in RNA synthesis, when stimulated at high cell densities. The data suggest that macrophages are not required for the initiation of lymphocyte activation. Their role in supporting mitosis may be the contribution of a second signal close to the G1/S boundary extending the size of the proliferating population.
A monoclonal antibody against human complement component C3: the production of C3 by human cells in vitro
Authors: Whitehead Alexander S. , Sim Robert B. , Bodmer Walter F.
Published: February 2007

A monoclonal antibody (WM1) against the third component of human complement (C3) was produced by fusing P3‐X63‐Ag8 mouse myeloma cells with spleen cells from BALB/c mice immunized with purified C3. The specificity of WM1 antibody against C3 was established by its capacity to inhibit a standard C3 hemolytic assay and to immunoprecipitate C3 from human serum in the presence of S. aureus bacteria. Indirect binding assays indicate that the antibody is directed against the C3c portion of C3. The immunoprecipitation technique was used to screen for the presence of C3 in the culture supernatants of various cell lines. By this means, C3 was identified as a secreted product of human primary fibroblasts, transformed fibroblasts and D98/AH‐2, a HeLa derivative, but not of other human cell lines. WM1 was unable to immunoprecipitate C3 from rabbit or mouse fibroblast culture supernatants.
Autologous mixed lymphocyte reactions in NZB mice: analysis in recombinant inbred lines shows a T cell defect unrelated to autoantibody production
Authors: Bocchieri Maureen H. , Riblet Roy J. , Smith J. Bruce
Published: February 2007

The autologous mixed lymphocyte reaction (AMLR) has been examined in the AMLR‐deficient strain, NZB, in C58 mice, which have normal AMLR responses, and in the (NZB × C58) recombinant inbred (NX8 RI) lines. Half of the NX8 RI lines had deficient AMLR and half were comparable in reactivity to the C58 parent strain. AMLR unresponsiveness did not correlate in the NX8 RI lines with H‐2 or any other marker known to affect immune recognition. Non‐T cells from H‐2k NX8 RI lines which had deficient AMLR were able to stimulate an MLR when cultured with T cells of C58 origin. AMLR‐positive H‐2d lines responded to NZB stimulators, whereas NZB T cells did not respond to any of the H‐2d NX8 RI lines but did exhibit strong alloreactivity. Thus, the AMLR defect in NZB mice is due to a T cell lesion. Furthermore, since AMLR deficiency in the NX8 RI lines did not correlate with a positive Coombs test or the production of naturally occurring thymocytotoxic antibody, we conclude that autoimmunity in NZB mice is a complex disease resulting from the inheritance of multiple independently segregating genes.
The Lyt phenotype of a long‐term allospecific T cell line. Both helper and killer activities to IA are mediated by Ly‐1 cells
Authors: Swain Susan L. , Dennert Gunther , Wormsley Susan , Dutton Richard W.
Published: February 2007

The relationship between surface antigen expression and function in the long‐term allospecific T cell line C.C3.11.75 was examined by flow microfluorometry, antiserum plus complement depletion and cell sorting. T cells of the line expressed Lyt‐1, but little or no Lyt‐2 antigens. Proliferation to cells bearing Iak determinants, generation of T cell‐replacing nonspecific helper factor in response to Iak‐positive cells and the killing of Iak‐positive targets were dependent only on Ly‐1 cells. No obvious heterogeneity was found in this cell line despite its disparate functional activities. The fact that Lyt‐2 molecules need not be present for killing directed against Ia determinants indicates that such molecules are not obligatory for the induction or delivery of killing and raises the question of what the role of Lyt molecules in T cell recognition or function might be.
Anti‐idiotypic immunity and autoimmunity I. In vitro and in vivo effects of anti‐idiotypic antibodies to spontaneously occurring autoantibodies to rat thyroglobulin
Authors: Zanetti Maurizio , Bigazzi Pierluigi E.
Published: February 2007

The effects of anti‐receptor (anti‐idiotypic) immunity on autoimmune responses have been investigated in Buffalo (BUF) rats with autoimmune thyroiditis. As compared to other animal models of autoimmune desease, BUF rat thyroiditis has the following advantages: it occurs in an inbred strain, arises spontaneously (i.e. without the experimental administration of autoantigens and adjuvants) and is characterized by the production of autoantibodies to only one autoantigen, thyroglobulin. Finally, its pathogenesis is mediated by autoantibodies to rat thyroglobulin, and therefore this model is particularly suitable to study the effects of anti‐idiotypic reactions on those autoimmune disorders whose damage is caused by humoral immunity.

The experiments reported in the present study show that first, heterologous anti‐idiotypic antibodies to autoantibodies against rat thyroglobulin have been produced and characterized. It has then been demonstrated that such anti‐idiotypic antibodies are capable of inhibiting the in vitro binding between thyroglobulin and thyroglobulin autoantibodies obtained from BUF rats. It has also been shown that repeated injections of anti‐idiotypic antibodies into sublethally X‐irradiated BUF rats with autoimmune thyroiditis were followed by a significant change in the levels of circulating autoantibodies to rat thyroglobulin. These results provide evidence that in spite of the complexity of autoantigens and the heterogeneity of autoimmune responses, established autoimmune diseases may be controlled by sequential immunosuppression and anti‐idiotypic immunity.
Different macrophage populations distinguished by means of fluorescent polysaccharides. Recognition and properties of marginal‐zone macrophages
Authors: Humphrey John H. , Grennan Deirdre
Published: February 2007

Fluorescent conjugates of hydroxyethyl (OEt) starch or Ficoll are selectively ingested and retained in vivo by spleen marginal‐zone (MZ) and lymph node marginal‐sinus macrophages of mice, whereas similar conjugates of type 3 pneumococcal capsular polysaccharide (SIII) are generally retained by macrophages (Kupffer cells, histiocytes, macrophages of spleen, lymph nodes, bone marrow and peritoneal cavity). MZ and other macrophages are readily identifiable by fluorescence after injection in vivo of OEt starch and SIII labeled with tetraethylrhodamine isothiocyanate and fluorescein isothiocyanate. Collagenase digestion was required for recovery of intact MZ macrophages from spleen in single cell suspensions and for maximum yields of other macrophages. MZ macrophages are larger and morphologically distinct from other macrophages, but resemble them in respect of EA, EAC receptors and acid phosphates and nonspecific esterase content and are equally radio‐resistant. They appear normal in CBA/N nude and in beige mice. Freshly isolated MZ macrophages in suspension have adherent lymphocytes, dispersible by EDTA treatment, with B but not T cell markers. It is suggested that selective adherence to MZ macrophages is a factor in determining B cell traffic. MZ macrophages did not have demonstrable surface I‐A or I‐EC antigens. Only 4–8% of other spleen macrophages freshly isolated by collagenase treatment expressed I‐A in the same preparation, whereas 35% of other cells (lymphocytes and blasts) reacted with monoclonal anti‐I‐A and anti‐I‐EC. After adherence to glass or plastic, 40% or more red‐pulp, but not MZ macrophages, became I‐A‐positive. When taken from mice recently restimulated with sheep erythrocytes, half the red‐pulp macrophages expressed I‐A even before adherence.

The relation of MZ to other macrophages is not known. However, their properties are consistent with the demonstrated ability of thymus‐independent antigens selectively taken up by these cells to elicit long‐lasting IgM antibody responses by direct interaction with B cells. The unexpected observation that only a small proportion of spleen macrophages freshly isolated from unstimulated mice had detectable surface I‐A, but that this proportion was much increased after attachment to plastic, is discussed in relation to the possibility that macrophages do not express surface Ia antigens unless they have been stimulated.
Preparative nonlytic separation of Lyt2+ and Lyt2− T lymphocytes, functional analyses of the separated cells and demonstration of synergy in graft‐vs.‐host reaction of Lyt2+ and Lyt2− cells
Authors: Mage Michael , Mathieson Bonnie , Sharrow Susan , McHugh Louise , Hämmerling Ulrich , Kanellopoulos‐Langevin Colette , Donald Brideau  , Thomas Charles A.
Published: February 2007

A convenient, preparative scale, nonlytic separation of mouse T lymphocytes into Lyt2.2+ and Lyt2.2− populations is reported. Immunoglobulin‐negative (Ig−) spleen cells, Ig− lymph node cells, and peanut lectin‐unagglutinated (PNA−) thymocytes were incubated under sterile conditions at 0°C with monoclonal mouse antibody to the Lyt2.2 T cell differentiation antigen. The antibody‐treated cells were washed and placed in polystyrene tissue culture dishes that had been precoated with antibody to mouse Ig. Nonadherent populations were depleted of Lyt2.2+ cells and were essentially devoid of cytotoxic T lymphocyte precursors (CTLp), but contained helper activity for in vivo T‐dependent IgM, IgG and IgA antibody formation. Adherent cell populations were enriched for Lyt2.2+ cells and for CTLp. The graft‐vs.‐host activity of the separated, adherent (Lyt2.2+) and nonadherent (Lyt2.2−) cells in the Simonsen spleen assay in neonatal (C57BL/6 × BALB/c)F1 mice was less than that of unfractionated cells, but the activity of remixed Lyt2.2+ plus Lyt2.2− cells was higher than the sum of the contributions of these cells tested separately, and equal to that of the unfractionated cells. PNA− thymocytes were also separated into Lyt2.2+ and Lyt2.2− populations by fluorescence‐activated cell sorting. Nonlytic separation allows the recovery of the Lyt1+2+ population, which is lost in cytotoxic elimination experiments. Under the conditions described for the plate separation, the purity of the separated cells and recovery of activity approaches that of cells separated by sorting. Therefore, the plate separation offers a convenient alternative to fluorescence‐activated cell sorting when large numbers (i.e. up to 5 × 107 positively selected cells) are needed, as in studies of in vivo cell‐mediated immune reactions.
Generation of effector cells from T cell subsets III. Synergy between Lyt‐1 and Lyt‐123/23 lymphocytes in the generation of H‐2‐restricted and alloreactive cytotoxid T cells
Authors: Simon Markus M. , Edwards Andrew J. , Hämmerling Ulrich , McKenzie Ian F. C. , Eichmann Klaus , Simpson Elizabeth
Published: February 2007

Lyt‐123/23 and Lyt‐1 T cell subsets, positively selected by separation on the fluorescence‐activated cell sorter, were tested in vitro for their role in the generation of H‐2‐restricted and alloreactive cytotoxic T cells. It is shown that in the proliferation assay, both T cell subsets responded equally well to H‐2 and non‐H‐2 antigens (H‐Y), respectively. In contrast, none of the selected Lyt subsets, but only the mixed population containing Lyt‐1 and Lyt‐123/23 lymphocytes gave rise to both H‐2‐restricted (anti‐H‐Y, anti‐trinitrophenyl) and alloreactive (anti‐H‐2) cytotoxic lymphocytes. The data imply an essential role of Lyt‐1 cells as inducers or helpers in the generation of all cytotoxic lymphocytes from their precursors in the Lyt‐123/23 pool.
Activation of the alternative pathway of complement: efficient fluid‐phase amplification by blockade of the regulatory complement protein β1H through sulfated polyanions
Authors: Bitter‐Suermann Dieter , Burger Reinhard , Hadding Ulrich
Published: February 2007

Current concepts of activation of the alternative pathway of complement (APC) focus on the central role of an amplification mechanism triggered by C3b which is covalently bound to the surface of activating substances. Using sulfated polyanions as model substances, an efficient fluid‐phase activation of complement is demonstrated in contrast to solid‐phase activation.

It is shown that particulate high‐molecular weight sulfated polyanions are capable of reversibly binding the guinea pig and human regulatory protein β1H. This fixation leads to an extensive activation of C3 and factor B because the regulatory function of β1H is blocked in the fluid‐phase C3b‐dependent amplification system of the APC. Addition of β1H to β1H‐depleted C4‐deficient guinea pig serum reconstitutes the physiological control mechanisms of the APC. Guinea pig β1H, purified to homogeneity, is described as a 160000 dalton protein of a single‐chain structure. In addition, highly specific and sensitive test systems for β1H are described.
Allotype suppression in the chicken IV. Deletion of B cells and lack of suppressor cells during chronic suppression
Authors: Ratcliffe Michael J. H. , Ivanyi Juraj
Published: February 2007

Embryonally induced allotype suppression in M‐1, G‐1 heterozygous chickens was stable for at least 18 months after hatching. Suppression was established rapidly since injection of antigen only 4 days after anti‐IgM‐1 antiserum failed to abrogate its effect. Injected chickens had undetectable serum levels (i.e. less than 40 μg/ml) of the suppressed IgM‐1 and low (0.3–0.6 mg/ml) levels of the linked IgG‐1 allotype. This correlated with a complete depletion of cells bearing the relevant IgM‐1 allotype and a compensatory increase in the alternative nonsuppressed IgM‐1 allotype‐bearing cells in the spleen, peripheral blood and bursa. Cell transfer studies suggested that suppression could not be attributed to allotype‐specific suppressor cells.
Implantation of mouse histocompatibility antigens into membranes of cultured tumor cells
Authors: Volsky David Julian , Ährlund‐Richter Lars , Dalianis Tina , Klein George
Published: February 2007

Membranes of murine lymphoma cells expressing H‐2a antigens were isolated, purified and co‐reconstituted with isolated Sendai virus envelopes according to a previously published procedure (Volsky, D. J. et al., Proc. Natl. Acad. Sci. USA 1979. 76: 5440.). The resulting hybrid H‐2a/Sendai virus envelope vesicles (SH‐2a vesicles) were capable of binding to and fusing with mouse lymphoma cells. The fusion resulted in the implantation of H‐2a antigens into membranes of target cells, as demonstrated by the presence of serologically active antigens on cultured cells 8 and 16 h after implantation.
b 96, a seventh allele at the rabbit x chain b locus
Authors: Benammar Amel , Cazenave Pierre‐André
Published: February 2007

A previously undetected allotypic specificity, A96, was observed in the wild rabbit population of Zembra (Tunisia). The A96 allotype is inherited as a b allotype, and its antigenic determinants are located on the x light chains of immunoglobulins. Although cross‐reacting with b6, the A96 allotype carries its own allotypic determinants, and is therefore distinct from the known allotypes of the b series (b4, b5, b6, b9, b4var and b95). The data indicate that A96 is encoded by an allele at the b locus, tentatively designated b 96.
Nature of the immunogenic moiety recognized by the human T cell proliferating in response to tetanus toxoid antigen
Authors: Broff Martin D. , Jonsen Marie E. , Geha Raif S.
Published: February 2007

This study was undertaken to investigate the nature of the immunogenic moiety recognized by the human T cell which proliferates in response to tetanus toxoid (TT) antigen.

Immunosorbent‐purified anti‐TT IgG antibodies failed, even when added in great excess, to inhibit T cell proliferation in response to TT. Urea‐denatured (UD) TT antigen containing less than 1% native TT, as assessed by its reactivity with antibodies raised against native TT, triggered proliferation in T cells to an extent equal to that seen with native TT. The proliferative response to UDTT was seen only in T cells obtained from donors immune to TT and was inhibited by antisera to DRw antigens of the cell donor. T cells responding to TT and to UDTT essentially overlapped because exposure to 5′‐bromo‐2‐deoxyuridine and light of T cells prestimulated with TT or UDTT abolished the specific response to both forms of the TT antigen but not to phytohemagglutinin or to Manilla antigen. It is concluded that proliferating human T cells recognize determinants which differ from those that elicit an antibody response and which may arise as a result of antigen processing by macrophages. The implications of these present results on the nature of the human T cell receptor for antigen are discussed.
Switched allotype expression in an immunoglobulin‐nonsecreting rabbit lymphoid cell line fused with rabbit gangliocytes
Authors: Petit‐Koskas Elisabeth , Schreiber Alain B. , Favre Catherine , Chemla Roselyne , Vray Bernard , Zurawski Vincent , Buttin Géarard , Cazenave Pierre‐andré , Strosberg A. Donny
Published: February 2007

The Simian virus 40‐transformed rabbit spleen cell TRSC‐1 synthesizes intracellular whole IgG molecules of the a1b4 allotype. Two hypoxanthine‐guanine phosphoryl transferase‐deficient mutants were derived from this line. One of these, TRSC‐1‐8, was used in somatic cell fusion experiments together with gangliocytes from a rabbit immunized against β‐galactosidase.

Out of nineteen hybrid clones surviving in selective medium, only one, L17, was shown to produce free γ chains which express the a2 allotype of the donor rabbit rather than the a1 marker of the parents TRSC‐1‐8 line. The inability to restore IgG secretion in hybrids suggests that dominant regulatory controls are exerted by the TRSC‐1 genome on Ig production. This supports the notion that the TRSC‐1 line originated from a splenocyte that had not reached the final plasmocyte differentiation stage at the time of viral transformation.
Liposomes as immunological adjuvants in eliciting antibodies specific to the synthetic polypeptide poly(LTyr, LGlu)‐poly(DLAla)–poly(LLys) with high frequency of site‐associated idiotypic determinants
Authors: Lifshitz Ruth , Gitler Carlos , Mozes Edna
Published: February 2007

The antibody response to the synthetic polypeptide, poly(LTyr, LGlu)‐poly(DLAla)–poly(LLys), [(T, G)‐A–L], injected entrapped in liposomes which served as adjuvant, has been analyzed. The liposomes used were composed of phosphatidylcholine, cholesterol, dicetylphosphate and DL α‐tocopherol (molar ratios as 4:3:0.1:0.5) and therefore, were negatively charged. Since the (T, G)‐A–L is also negatively charged, no free complexes were formed. The (T, G)‐A–L was found to be entrapped inside the enclosed volume of the liposomes, and no (T, G)‐A–L antigenic determinants could be detected on the liposomal membranes. Injection of high‐responder C3H.SW (H‐2b) mice with (T, G)‐A–L‐bearing liposomes demonstrated that the i.p. and the i.v. routes of immunization were efficient in eliciting (T, G)‐A–L‐specific antibodies, whereas the i.d. injection led to poor antibody responses. The latter route of immunization is the most effective when (T, G)‐A–L is injected in complete Freund's adjuvant (CFA). When low doses (0.1 and 1 μg) of (T, G)‐A–L were used for immunization, the liposomes were better adjuvants than CFA. The effectiveness of the liposomes as immunological adjuvants was also shown in their ability to induce high‐potential, primed memory cells. The pattern of low (H‐2k, a) and high (H‐2b) responsiveness to (T, G)‐A–L was retained following immunization with (T, G)‐A–L entrapped in liposomes, as tested in two pairs of congenic strains. (T, G)‐A–L‐specific antibodies induced by injection with 1μ antigen entrapped in liposomes bear the (T, G)‐A–L site‐related idiotypic markers of C3H.SW (Igh‐1a) mice in a significantly higher frequency than the homologous idiotypes, namely the antibodies elicited in this strain against (T, G)‐A–L in CFA. Thus, liposomes may serve as adjuvants for the production of relatively restricted (T, G)‐A–L‐specific antibodies of high qualitiy.
Cellular interactions in the generation of cytolytic T lymphocyte responses Analysis of the helper T cell pathway
Authors: Weinberger Ofra , Herrmann Steven , Mescher Matthew F. , Benacerraf Baruj , Burakoff Steven J.
Published: February 2007

Murine splenic lymphocytes exhibit a requirement for helper T cells for the induction of a cytolytic T lymphocyte response to suboptimal doses of allogeneic cells, membranes from allogeneic cells, or purified H‐2 antigen in liposomes. The conditions where a requirement for help is apparent are the same conditions where a dependence on splenic adherent cells (SAC) has been demonstrated (Weinberger, O. et al., Proc. Natl. Acad. Sci. USA 1980. 77: 6091). Help can be provided in the form of primed, radioresistant, Ly‐1+ spleen or lymph node cells or helper factor (interleukin 2, IL‐2). A factor generated from phytohemagglutinin‐stimulated human lymphocytes, when added to culture in the presence of antigen, bypassed the requirement for Ia+ SAC and helper cells. IL‐2 reconstituted the response to H‐2Kk in liposomes in cultures depleted of SAC, strongly suggesting that the helper cell must see antigen re‐expressed by an antigen‐presenting cell, whereas the prekiller does not. IL‐2 could be generated by culturing Ly‐1+ murine spleen cells with H‐2Kk pulsed on SAC.
Sequential expression of B lymphocyte surface antigens in vitro
Authors: Abbott Joan , Ngiam Kin
Published: February 2007

Serological techniques were used to examine the process of sequential surface antigen expression on differentiating B cells in vitro. A 4‐day culture system is described in which bone marrow lymphocytes from neonatal mice acquire in sequence the ability to express Lyb‐2, IgM, Ia and IgD in response to a 3‐h‐induction with E. coli lipopoly‐saccharide (LPS). Lyb‐2 can be induced on day 1, IgM can be induced after 24 h, Ia after 48 h and IgD only after 96 h in culture. This sequence mimics the order of appearance of B cell surface antigens during ontogeny. When DNA synthesis is blocked from 0–24 h with hydroxyurea (HU), all surface antigens can be induced simultaneously by LPS. Immunoselection of one antigen‐bearing population results in the loss of cells bearing other B cell antigens indicating that the surface antigens are induced on the same cells. When both HU and LPS were added to the cultures from the start, IgM appears after 11–14 h, Ia after 14–15 h and IgD only after 19 h. Induction of antigen was demonstrated by the cytotoxicity assay, quantitative absorption and the protein A sheep red blood cell resetting assay.

The results obtained show that there is a population of surface IgM‐negative precursor B cells in young bone marrow which, when grown in vitro, become sequentially inducible for expression of B surface antigens. Inhibition of DNA synthesis promotes acquisition of the inducible state, and the sequence of antigen expression is correlated with specific time intervals after DNA synthesis has stopped.
Compensation for idiotype suppression I. Acquirement of ability to compensate for TEPC‐15 idiotype suppression in mice during the early neonatal period
Authors: Kim Byung S. , Hubchak Susan
Published: February 2007

Neonatal injection of BALB/c mice with antibodies specific for the idiotype of TEPC‐15 myeloma protein (T15id), which is serologically identical to the major idiotype of anti‐phosphorylcholine (PC) antibody, renders the recipients completely unresponsive to PC. C57BL/6, (BALB/c × C57BL/6)F1 and C.B20 mice, similarly treated with anti‐T15id antibody, also displayed tolerance to PC although they were relatively more resistant (8–13%) than BALB/c mice (<2% control response). When anti‐T15id antibody was injected into 15‐day‐old neonates, the resistance to the tolerance in C57BL/6 and C.B20 mice was much more apparent (up to 80% of the control response) in contrast to that in BALB/c mice, which was not significant. Adoptive transfer of spleen cells from idiotypically suppressed BALB/c mice into 20‐day‐old normal C.B20 mice resulted in suppression of T15id but not in tolerance to PC, due to increased production of non‐T15id‐bearing anti‐PC antibody. These results suggest that the ability of clonal compensation for T15id suppression is acquired during early life (2–10 days), under the influence of gene(s) associated or linked with the Igh.
Cross‐reactive anti‐vesicular stomatitis virus (VSV) cytotoxic T lymphocytes recognize the major surface glycoprotein of VSV
Authors: Hale Arthur H. , Ruebush Mary J. , Lefrančlois Leo
Published: February 2007

The major surface glycoprotein (G) of vesicular stomatitis virus (VSV) was purified and incorporated into lipid vesicles containing the purified hemagglutinin‐neuraminidase (HN) and fusion (F) glycoproteins of Sendai virus. These lipid vesicles were then used to modify and render target cells susceptible to lysis by anti‐VSV cytotoxic T lymphocytes. The results obtained provide direct evidence that the G protein is a target antigen for specific and cross‐reactive anti‐VSV cytotoxic T lymphocytes. The significance of this work is discussed.
Lyt phenotypes of primary cytotoxic T cells generated across the A and E region of the H‐2 complex
Authors: Vidovic Damir , Juretic Antonio , Nagy Zoltan A. , Klein Jan
Published: February 2007

Six different cell‐mediated lympholysis (CML) combinations were established, four of which generated effector cells against the I‐E, and two against the I‐A molecule. The cell surface phenotype of effector cells was then determined by depletion of cytotoxic T lymphocyte (CTL) activity with antisera and rabbit complement (C) treatment. Both types of effector cells were completely eliminated by treatment with anti‐Thy‐1.2 antiserum plus C. Anti‐Lyt‐1.2 and C depleted anti‐A and anti‐E killer activity but did not eliminate CTL generated across a whole H‐2 difference. One out of three different batches of anti‐Lyt‐2.2 antiserum did not deplete anti‐A killer activity, while it efficiently eliminated CTL generated across the E region or whole H‐2 difference. However, two batches of anti‐Lyt‐2.2 antiserum depleted also anti‐A CTL activity. A quantitative difference between anti‐A and anti‐E CTL in terms of Lyt‐2 expression was demonstrated by significant differences in recovery of killer activity, after treatment of these two types of CTL with a wide concentration range of the same anti‐Lyt‐2.2 antiserum and C. Thus it is concluded that anti‐A killer cells have the cell surface phenotype of Thy‐1+, Lyt‐1, Lyt‐2↑, whereas anti‐E CTL are Thy‐1+, Lyt‐1↑, Lyt‐2←. The data are discussed in the context of a possible association of Lyt phenotypes of T cells with the type of MHC antigens they recognize.
The identification of specific antigens in circulating immune complexes by an enzyme‐linked immunosorbent assay: detection of bovine x‐casein IgG complexes in human sera
Authors: Cunningham‐Rundles Charlotte
Published: February 2007

Circulating immune complexes have been implicated in the development of tissue injury in many chronic disease states, but in most instances the inciting antigens have not been identified. This report describes the development of a sensitive enzymelinked immunosorbent assay which can be used to screen rapidly and simultaneously the immune complexes of numerous sera for the presence of a suspected antigen. The prototype antigen sought here was x‐casein, a frequent participant in immune complex formation in IgA deficiency and in atopic diseases. The enzyme‐antibody conjugate described here can detect as little as 0.11 ng/ml of x‐casein for immune complexes formed in vivo or in vitro, one can distinguish circulating complexes containing casein from complexes not containing this antigen. Using this reagent, a major antigen in the immune complexes of hypogamma‐globulinemic patients treated with intravenous γ‐globulin was unexpectedly identified as x‐casein. This method of specific immune complex analysis is suggested as a practical and effective approach to the elucidation of the antigenic constituents of immune complexes found in many diseases.
Regulation of ongoing IgE antibody responses with minute doses of antigen
Authors: Jarrett Ellen E. E. , Hall Elizabeth
Published: February 2007

Repeated challenge of egg albumin‐immunized Hooded Lister rats with a tiny amount of antigen presents a stimulus not only to effector cells for an IgE response but also to a related class‐selective suppressive mechanism which eventually becomes predominant. The results obtained suggest that IgE responsiveness is abrogated by exposure to an antigen dose which is several orders of magnitude lower than required for the regulation of antibody of other classes.
Genetic and antigenic requirements for induction of T helper cells for anti‐Sendai virus‐specific antibody production
Authors: Ertl Hildegund Christa Johanna
Published: February 2007

T helper cells for the promotion of Sendai virus‐specific antibody production were generated in vitro. They could be stimulated by infectious, UV light‐inactivated or fusion‐negative Sendai virus, which had to be presented by adherent cells. Induction of T helper cells was virus‐specific and required H‐2 IA region compatibility between T cells and antigen‐presenting cells. Delivery of help to B lymphocytes was neither virus‐specific nor H‐2‐restricted.
Functional activities of antibodies against brain‐associated T cell antigens I. Induction of T cell proliferation
Authors: Jones Barry , Janeway Charles A.
Published: February 2007

Rabbit anti‐mouse brain antiserum mediated an in vitro cooperative interaction between Ig‐anti‐Ig column‐purified Lyt‐1+, Lyt‐2− T cells and spleen B cells. DNA synthesis in the B cells was inhibited with mitomycin C, and the T cell proliferative response was measured by [3H]thymidine incorporation after 24 h of culture. The T‐B cell interaction was genetically unrestricted, and the accessory function of the B cell was engaged via interaction with the Fc portion of the T cell‐bound anti‐mouse brain antibody since the F(ab′)2 fragment was inactive. The rabbit anti‐mouse brain antiserum appears to recognize a unique antigenic determinant in the T cell membrane which triggers proliferation. Although brain‐absorbed, rabbit anti‐mouse thymocyte antiserum contained antibodies which bound to the T cell surface, it was incapable of inducing T cell proliferation. Furthermore, the Thy‐1 molecule itself did not appear to be involved because allo‐ and xenoantisera against the allelic determinants were inactive, and the capping of Thy‐1.2 from the T cell surface did not prevent the binding of the mitogenic component in rabbit anti‐mouse brain antiserum.

The T cell reaction to anti‐brain antiserum is unlike the antigen‐specific T cell response in being genetically unrestricted. It is possible that the antibody operates via the perturbation of a T cell determinant involved in the binding of T cell growth factors, and/or reception of B cell feedback signals.
Involvement of the spleen in the control of the immunogenic and phagocytic function of thioglycollate‐induced macrophages
Authors: Ron Yacov , De Baetselier Patrick , Feldman Michael , Segal Shraga
Published: February 2007

The immunogenic capacity of thioglycollate‐induced peritoneal macrophages of adult splenectomized animals was compared to that of macrophages of sham‐operated controls. Macrophages from splenectomized animals were found to be impaired in their function as antigen‐presenting cells, both in the education of virgin initiator T lymphocytes and in the stimulation of antigen‐specific T memory cells. Macrophages from splenectomized animals were also severely impaired in their phagocytic capacity, as assessed in an opsonin‐dependent bacterial phagocytosis assay. However, they were not impaired in their ability to pynocytose soluble keyhole limpet hemocyanin. These results indicate that the spleen may play a dicisive role in controlling the differentiation of peritoneal macrophages.
Cyclosporin A mediates immunosuppression of primary cytotoxic T cell responses by impairing the release of interleukin 1 and interleukin 2
Authors: Bunjes Donald , Hardt Conny , Röllinghoff Martin , Wagner Hermann
Published: February 2007

The site of action of the immunosuppressive drug cyclosporin A in in vitro cytotoxic allograft responses has been localized. General cytotoxic effects of the drug on proliferating T cells became apparent at concentrations of 500–1000 ng/ml, while selective effects were observed at concentrations of 10–100 ng/ml. The selective effects included a blockade of interleukin 2 release from activated T helper cells on the one hand and inhibition of interleukin 1 release from splenic adherent cells on the other. While cyclosporin A did not interfere with the intracellular events required for the activation and subsequent clonal expansion of alloreactive T cells, the lack of interleukin 1 and interleukin 2 induced by cyclosporin A results in an inability of T responder cells to mount cytotoxic allograft responses in vitro.
Dynamics of antibody‐ and lectin‐mediated endocytosis of hapten‐containing liposomes by murine macrophages
Authors: Geiger Benjamin , Gitler Carlos , Calef Edna , Arnon Ruth
Published: February 2007

The uptake by murine macrophages of liposomes, exhibiting one of a variety of haptenic groups on their surfaces, was greatly enhanced by the addition of an intact antibody or a lectin specific for the incorporated hapten. The uptake of untreated liposomes was slow and linear over long periods, whereas upon addition of the antibody or lectin, over 30‐fold increase in the maximal rate of uptake was observed. The process reached a plateau after 90–120 min. The interaction of the antibody‐ or lectintreated liposome with the macrophages apparently resulted in an active endocytosis of the vesicles. As observed by fluorescence microscopy, the distribution of a water‐soluble fluorescent, intraliposomal marker had a granular intracellular pattern in treated cells. The uptake was sensitive to azide and the liposome constituents could not be detected at the cell surface. The size of the liposomes as well as the state of stimulation of the macrophages (thioglycollate stimulated vs. normal) did not seem to have a major effect on the phagocytic process. The time required to reach the plateau in uptake was independent of liposome composition or antibody concentration and is, apparently, an intrinsic property of the cells. The implication of this phenomenon on the dynamics of the relevant macrophage receptors is discussed.
Induction of anamnestic T cell proliferation by antigen‐pulsed, bone marrow‐derived macrophages
Authors: Reske‐Kunz Angelika B. , Spaeth Eberhard , Reske Konrad , Lohmann‐Matthes Marie‐Luise , Rüde Erwin
Published: February 2007

Bone marrow‐derived macrophages (BMMϕ) were grown in a liquid culture system in the presence of L cell‐conditioned medium as a source of colony‐stimulating factor. After a 4‐h pulse with antigen, cultured irradiated BMMϕ were capable of presenting the antigen to primed T cells as assessed in a T cell proliferation assay. Proliferation was optimal when BMMϕ were used between days 5 and 8 of bone marrow cell culture. T cells of Lytl and Lyt123 phenotype had to be present at the start of the culture period to yield an optimal response. Conventional antisera and monoclonal antibodies directed against the H‐2 I region and the I‐A subregion, respectively, proved inhibitory in this system. Cultured BMMϕ from low‐responder strains failed to present antigens under immune response gene control in a form that was immunogenic to T lymphocytes. Cultured BMMϕ might thus serve as a source of antigen‐presenting cells in the study of cell‐cell interaction and immune response gene regulatory mechanisms.
Phagocytosis and degradation of DNA‐anti‐DNA complexes by human phagocytes. II. Influence of the size of the complexes
Authors: Lamers Marinus C. , de Groot Elisabeth R. , Roos Dirk
Published: February 2007

The influence was studied of the size of DNA‐anti‐DNA complexes on their capacity to induce phagocytosis and degradation by monocytes and neutrophils from human blood. An estimate of the size of the complexes was obtained by precipitation analysis, sucrose‐gradient velocity sedimentation and filtration over Nucleopore filters. The results show that only those complexes are processed that precipitate in 15 min at 3000 × g. These complexes have an S value of more than 25 000 and a diameter of more than 0.4 μm. Likewise, tetanus‐anti‐tetanus complexes also had to be precipitable in 15 min at 3000 × g to be processed by the phagocytes.
Clearance of sensitized erythrocytes in NZB/NZW mice Effects of castration and sex hormone treatment
Authors: Shear Hannah Lustig , Roubinian Jirayr R. , Gil Paul , Talal Norman
Published: February 2007

The clearance of particulate immune complexes consisting of erythrocytes sensitized with IgG or complement was investigated in (NZB × NZW)F1 (B/W) mice. Treatment of castrated B/W mice with androgen or estrogen was able to modulate this clearance.

Young (3‐month‐old) male and female B/W mice cleared IgG‐sensitized mouse erythrocytes rapidly, whereas older males (13 months) and females (7 months) showed a marked impairment in their ability to clear these cells. In addition, erythrocytes sensitized with complement in the absence of antibody were cleared within 5 min in young B/W mice. Older mice showed a greater and more rapid clearance rate of these cells.

Castrated female B/W mice treated with androgen implants from three weeks of age showed improved clearance of IgG‐sensitized erythrocytes at 7 months, whereas estrogen‐treated male mice showed delayed clearance.

These results suggest an age‐dependent defect in the clearance of IgG‐sensitized particles, perhaps due to diminished levels of serum complement and/or saturation of Fc receptors. In addition, there is an alteration in the clearance of complement‐sensitized erythrocytes which may be related to changes in macrophage activity or enzyme inactivators of C3 and C4. The possible mechanisms responsible for the hormonal modulation of clearance are discussed in relation to the known ability of these hormones to influence autoimmune diseases.
Purification and characterization of an immunosuppressive factor from ovarian cancer ascites fluid
Authors: Oh Se‐Kyung , Moolten Frederick L.
Published: February 2007

A nonspecific immunosuppressive factor present in malignant (ovarian carcinoma) ascites fluid has been purified by acid extraction from a high molecular weight ( > 200 000) complex followed by preparative isoelectric focusing on Bio‐lyte media. It is an acidic protein (pI = 3.6) of mol. wt. 50 000 to 52 000 as estimated by gel filtration and composed of subunits of 25000 to 26000 estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis, under reducing conditions. It inhibits the phytohemagglutinin‐dependent mitogenic response of normal peripheral blood lymphocytes by 50% at 2 μg/ml concentrations in vitro and suppresses 80% of the plaque‐forming cell response to sheep erythrocytes at 100 μg per mouse in vivo. Its chemical identity with any of the known plasma proteins has not been established. Its failure to stain with periodic acid Schiff's reagent indicates its minimal content of carbohydrates. It is susceptible to tryptic and pronase digestion but insensitive to deoxyribonuclease and ribonuclease digestion. A smaller suppressive factor identified in the same fluid appears to be a lymphotoxin; it differs from the acid‐extracted nonspecific suppressive factor in its lack of susceptibility to trypsin.
Consequences of adenosine deaminase deficiency on thymocyte metabolism
Authors: Thuillier Laure , Garreau Florianne , Cartier Pierre H.
Published: February 2007

Using 2′‐deoxycoformycin inhibition of adenosine deaminase as a model of adenosine deaminase deficiency, the effects of 10 μM 2′‐deoxyadenosine (dAdo) on the metabolism of concanavalin A (Con A)‐stimulated rat thymocytes were studied. When dAdo and Con A were added simultaneously, a strong inhibition of the incorporation of [3H]thymidine (84%); [3H]uridine (98%) and L‐[3H] leucine (46%) in the acid‐insoluble fraction, and of [14C]formate (78%) and H14CO3− (43%) uptake is observed after 48 h of incubation. When dAdo is added after 12 h of Con A stimulation, no such inhibition is observed, but when added after 24 h of stimulation, there is an enhancement of blastogenesis as measured by nucleic acid, protein, and purine and pyrimidine base synthesis. More detailed studies of thymocytes stimulated by Con A for 0–72 h, followed by short‐term incubation periods with dAdo (1–5 h), revealed that thymocyte metabolism becomes progressively less sensitive to dAdo‐mediated inhibition during the course of blastogenesis.