The response of the foetal lamb to maternal lymphocytes

Foetal lambs were inoculated with either maternal or third-party lymphocytes. Of foetuses transfused in the first half of pregnancy (from 49 to 73 days), one quarter survived until the fifth month. Examination of the immunological reactivity of these survivors revealed that all rejected skin grafts from the lymphocyte donors and manifested normal mixed lymphocyte reactivity. In two instances, responsiveness of the transfused lambs to normal lymphocyte transfer was reduced. Foetal lambs transfused with large numbers of maternal lymphocytes in the last third of pregnancy could survive provided the donor ewe had not been sensitized against foetal or paternal determinants. Following intravenous challenge with maternal lymphocytes, cells collected over a prolonged period from the thoracic duct of the foetal recipient exhibited depression of anti-maternal reactivity in mixed lymphocyte culture.

A search for an enriched source of polymeric IgA in human thoracic duct lymph, portal vein blood and aortic blood

Because human bile contains a lot of secretory IgA, it has been suspected that the human liver, like rat liver, transfers polymeric IgA from plasma to bile. Hence, a rich source of polymeric IgA might enter the general circulation of man. We examined human thoracic duct lymph, portal vein blood and aortic blood for content and molecular size of IgA. None of the fluids was found to have either a higher total concentration of IgA or a higher proportion of polymeric IgA than that found in peripheral venous blood. It is possible that hepatic clearance of plasma IgA does not occur in man to the extent that it does in the rat, and a relatively larger proportion of human biliary IgA might originate from synthesis in hepatobiliary tissues.

Kinetics of extravasation and redistribution of IgA-specific antibody-containing cells in the intestine

Double Thiry-Vella loops were prepared in rats, each locally immunized with a different antigen, and the kinetics of appearance in the loops of antibody-containing cells (ACC) specific for each antigen was recorded. The results confirm, under more rigorously controlled conditions, the conclusions of previous work that the initial appearance of IgA lymphoblasts in the intestinal lamina propria occurs independently of antigen. In addition, these findings are extended by demonstrating 1) that there is no specialized site within the intestinal lamina propria for ACC to enter the tissue; 2) that in immunized intestine, specific ACC progressively accumulate around the crypt regions; and 3) that a proportion of this specific accumulation can be accounted for by ACC proliferation within the lamina propria.

Cellular dissemination of priming for a mucosal immune response to cholera toxin in rats

Using CT as the test antigen, we sought 1) to learn whether primary immunization at 1 mucosal site caused priming of distant nonstimulated mucosae, 2) to study the role of migrating memory cells in the dissemination of mucosal priming, and 3) to compare disseminated priming with priming that occurs at the site of initial immunization. CT given i.c. or i.d. caused priming in tracheal and nonexposed enteric mucosae; i.t. immunization, however, did not cause detectable enteric priming. Adoptive transfer of immune TDLs showed that priming was conveyed by migrating memory cells. These appeared to be of 2 types: those that recirculated briefly before settling in MALT, and those that continued to recirculate until recruited by antigen to the site of mucosal challenge. Both types were required for secondary responses at mucosae distant from the site of priming. The time-course of disseminated mucosal priming resembled that of priming at the site of initial CT exposure, both lasting at least 16 wk. Disseminated priming persisted better in jejunal than tracheal mucosa, suggesting that the subgroup of memory cells that did not continue to recirculate settled preferentially in jejunal MALT. Disseminated priming supported smaller challenge responses than priming at the site of initial CT exposure did, suggesting that sessile memory cells also contributed to the latter process. These observations extend the concept of a "common mucosal immune system" to include cellular dissemination of mucosal priming, but also show quantitative differences between local and disseminated priming that probably reflect the patterns of distribution of migrating and sessile memory cells.

Immunoglobulin isotype expression. II. Frequency analysis in mitogen-reactive B cells

The frequency of lipopolysaccharide (LPS)-reactive B cells developing into clones that secrete the various immunoglobulin (Ig) classes has been determined in vitro, in cells from BALB/c mice, under culture conditions which detect all growth-inducible cells. Secretion of the different Ig classes was assessed in the protein A plaque assay for Ig-secreting, plaque-forming cells by using developing antisera specific for either IgM, IgG1, IgG2a, IgG2b, IgG3 or IgA. In all lymphoid organs tested (spleen, bone marrow, mesenteric lymph nodes and thoracic duct), a considerable proportion of all B cells (5-20%) was induced by LPS to yield a clone of IgM-secreting cells. Frequency determinations of LPS-reactive cells giving rise to descendants secreting other Ig isotypes revealed that, on an average, and irrespective of the origin of the cells, 7% of all IgM-secreting clones switched to the synthesis of IgG1, 39% to IgG2, 41% to IgG3 and 1% to IgA. Roughly the same frequencies of B cells switching CH gene expression were found among spleen cells of athymic nude mice. No correlation was found between the clonal frequencies of CH gene expression in polyclonally activated B cells and the in vivo "background" Ig-secreting cells suggesting that the CH gene expression in B cells is influenced by the quality of stimulation and other regulating influences.

Lymphocyte recognition of lymph node high endothelium. III. Enhancement by a component of thoracic duct lymph

The first step in the entry of blood lymphocytes into lymph node is the binding of these cells to venules lined by high endothelium (HEV). This recognition event has been studied using a model system in which rat thoracic duct lymphocytes (TDL) adhere selectively to HEV when overlaid onto lymph node sections. We now report that this binding is increased by a lymph fraction designated adherence enhancing factor (AEF). Lymph depleted of cells and chylomicra was fractionated with (NH4)2SO4. Material that precipitated between 60 and 80% saturation was dissolved in buffer and extracted with chloroform/methanol; the aqueous phase was used as the source of AEF. The factor was nondialyzable, trypsin sensitive, and heat stable (70 degrees C, 30 min). Lymph node sections pretreated with AEF showed a 2- to 3-fold increase in the number of TDL bound to HEV and a 5 to 10-fold increase in the number of HEV with more than 5 adherent lymphocytes. The effect of AEF was specific: 1) No increase in lymphocyte binding to non-HEV areas of the tissue section occurred. 2) The binding of both TDL and spleen lymphoid cells to HEV was enhanced, but thymocyte attachment was not promoted. We conclude that AEF has biologic properties that might enable it to play a physiologic role in lymphocyte recirculation.

Adoptive transfer of total and parasite-specific IgE responses in rats infected with Nippostrongylus brasiliensis

Infection of rats with Nippostrongylus brasiliensis has both a parasite-specific and non-specific IgE stimulating effect. Both these responses can be adoptively transferred with thoracic duct lymphocytes (TDL) from infected rats. The character of the IgE response in the recipient rats was related to the stage after infection of the cell donors. TDL from hyperimmune rats adoptively transferred high serum titres of parasite-specific IgE to infected recipient rats and substantially increased the levels of total IgE. However, adoptive immunization with TDL from donors infected 10 days previously did not stimulate parasite-specific IgE and only slightly increased total IgE levels. After cell fractionation the sIg- cells from day 10 TDL increased the level of total IgE but not parasite-specific IgE whereas sIg- cells from hyperimmune TDL did not induce any IgE response unless given with sIg+ cells. The possible reasons for this are discussed.

Renal transplantation after thoracic duct drainage

Forty-seven patients treated by at least 28 days of thoracic duct drainage (TDD) before cadaveric renal transplant are compared with 63 patients treated with standard immunosuppression. The TDD patients were begun on half the dosage of steroids, and at 30 days were receiving approximately two-thirds the dose that the non-TDD patients received. Acute rejection occurred in 35% of the TDD group, as compared with 61% of the non-TDD group. Graft survival in the TDD patients was twice as good as the non-TDD patients at all time intervals. The patient survival rates were not significantly different between the two groups. TDD pretransplant favorably affects cadaveric renal allograft survival for at least five years.

DR-bearing T lymphocytes in thoracic duct lymph

T cells having DR antigens were shown to be present in high numbers in the thoracic duct lymph of patients undergoing long-term drainage. As drainage progresses the proportion of T DR cells in the lymph increases to levels as high as 70% at 6 weeks. These cells were demonstrated by showing that T cells isolated by sheep red cell rosetting were killed by the action of rabbit anti-B-cell sera and of HLA-DR antisera. The HLA-DR specificities found on the T cells corresponded with those on the patients’ B lymphocytes.

Lymphocyte recognition of lymph node high endothelium. I. Inhibition of in vitro binding by a component of thoracic duct lymph

Rat thoracic duct lymphocytes (TDL) adhere selectively to HEV when overlaid onto glutaraldehyde-fixed frozen sections of lymph node. The results presented demonstrate that thoracic duct lymph contains a factor capable of inhibiting this reaction. A crude preparation of inhibitory factor was isolated from cell and chylomicron-free lymph by (NH4)2SO4 precipitation (60 to 80% saturation). Sephacryl S-200 chromatography revealed 4 major peaks. The inhibitory factor was detected in peak I but not in the others. Similarly peak I but not peak II or III inhibited HEV binding of lymphocytes from lymph nodes and spleen. Peak I emerged near aldolase (m.w. 160,000) and was enriched approximately 50-fold compared to the crude preparation. In addition, experiments employing a rabbit peak I antiserum provided evidence that molecules responsible for inhibition were antigenically related to structures present on TDL but not on thymocytes. It is suggested that inhibitory factor possesses an affinity for lymphocyte binding sites of high endothelium and is derived from shed TDL surface components that play a role in adherence to HEV of lymph nodes.

Lymphocyte recognition of lymph node high endothelium. II. Characterization of an in vitro inhibitory factor isolated by antibody affinity chromatography

Thoracic duct lymph contains a factor that inhibits in vitro adhesion between lymphocytes and high endothelial cells. Crude inhibitory factor was isolated from lymph by (NH4)2SO4 precipitation and partially purified by using an immunoabsorbant column of rabbit anti peak I Ig coupled to Sepharose 4B. Antibody affinity chromatography separated the HEV binding inhibitory factor from the bulk of protein in the crude preparation; activity was enriched 50-fold. The results show that the effect of the factor was exerted on high endothelial cells; both glutaraldehyde-fixed HEV and unfixed mouse HEV were susceptible to the action of this material. In contrast, the HEV binding properties of lymphocytes were unaffected by the factor. Inhibitory activity was destroyed by treatment with trypsin or exposure to 100 degrees C but was unaffected by incubation at 56 or 70 degrees C for 30 min. In addition, the factor bound to lentil lectin and was eluted with alpha-methyl-D-mannoside. Together these findings indicate that the HEV binding inhibitory factor is a glycoprotein.

Polyclonal activation of human lymphocytes in vitro-II. Reappraisal of T and B cell-specific mitogens

The capacity of the T cell mitogens phytohemagglutinin (PHA), concanavalin A (Con A), pokeweed mitogen (PWM), and Staphylococcus protein A (SpA) to induce B cell proliferation and differentiation was compared with the B cell mitogen, formalinized Staphylococcus aureus (STA). Lymphocyte subpopulations from normal donors and patients with various immunodeficiency diseases were studied. In the presence of the T cell mitogens, irradiated T cells were capable of providing a helper cell activity that enabled co-cultured B lymphocytes to proliferate in response to these mitogens and to differentiate into IgM-secreting (direct) hemolytic plaque-forming cells (PFC). In the PFC response, radioresistant T-helper and radiosensitive T-suppressor cell activities could be demonstrated. T-suppressor cell activity outweighed helper activity only in nonirradiated co-cultures stimulated with Con A. Patients with severe combined immunodeficiency lacked mitogen-induced helper T cells, whereas patients with various forms of humoral immune deficiency were normal in this respect. These findings and the tissue distribution of the helper activity is aquired early in post-thymic T cell differentiation. The data suggest that experiments with cell lineage-specific lymphocyte mitogens should be considered in the context of more complex cell-cell interactions.

Suppression of experimental allergic encephalomyelitis with thoracic duct lymphocytes

Thoracic duct lymphocytes (TDL) from Lewis rats immunized 9-10 days previously with basic protein in complete Freund's adjuvant (BP-CFA) failed to induce experimental allergic encephalomyelitis (EAE) in syngeneic recipients. This contrasts with the successful transfer of EAE by lymph node cell suspensions from donors immunized 9 days previously with BP-CFA. Only minor EAE was induced passively by TDL from rats immunized 11-12 days before with BP-CFA. TDL collected 9-20 days after BP-CFA immunization, however, were successful in transferring specific suppression of EAE tested by the lack of disease in the recipients immunized actively with BP-CFA 1 week after the TDL transfer. The data indicate that the thoracic duct contains specific suppressor cells shortly before, during and after the development of clinical EAE.

Priming and suppression of the intestinal immune response to cholera toxoid/toxin by parenteral toxoid in rats

Parenteral immunization of rats with cholera toxoid had both priming and suppressive effects upon the antitoxin response in jejunal lamina propria to locally applied toxoid/toxin. Priming was detected when parenteral toxoid was given i.p. but not i.v. or s.c., was enhanced by Freund's adjuvant, and appeared to reflect enhanced encounter of i.p. antigen with IgA-committed lymphocytes in extra-intestinal mucosa-associated lymphoid tissue. In contrast, suppression followed parenteral toxoid given i.p., i.v., or s.c.; suppression was antigen specific and lasted at least 16 weeks. Parenteral toxoid suppressed both primary and secondary types of mucosal antitoxin responses, ultimately preventing the generation of antitoxin-containing immunoblasts from Peyer's patches. Since suppression followed parenteral immunization by routes that did not provoke mucosal priming, it was, at least in those instances, not simply a regulatory consequence of mucosal priming. These results support the notion that priming and suppression of a specific mucosal immune response are independent effects of parenteral immunization that are probably determined by the distribution of antigen to mucosa-associated and systemic lymphoid tissue, respectively.

Antigen-laden cells in thoracic duct lymph. Implications for adoptive transfer experiments

T cells from thoracic duct lymph of donor rats suppress the adoptive secondary response to human serum albumin (HSA). The original aim of the present investigation was to determine whether these non-immune cells have antigen-specific receptors. Thoracic duct lymphocytes (TDL) were depleted in vivo of antigen-specific T cells (negatively selected) by acutely injecting non-immune donors with HSA at the time of thoracic duct cannulation. Negatively selected TDL were mixed with memory cells (primed TDL from previously immunized donors) and transferred into irradiated recipients to assess whether the suppressive potential had disappeared. Paradoxically, the addition of negatively selected TDL (which were unresponsive to HSA) augmented the adoptive secondary anti-HSA response. Further study showed that the augmented response was mediated by a very small number of cells (∼ 1 in 5000) laden with antigen that appeared in lymph of non-immune donors following HSA injection. These antigen-bearing cells were highly immunogenic and furthermore could overcome the effects of T suppressor cells in vivo. Once antigen laden cells were removed from lymph (by affinity chromatography), however, negatively selected TDL were found to inhibit the adoptive secondary response suggesting that either suppression in this model is non-specific or that antigen-specific suppressor cells are not selected out of the recirculating pool by antigen.

In vitro adherence of lymphocytes to unfixed and fixed high endothelial cells of lymph nodes

Rat thoracic duct lymphocytes (TDL) bind selectively to venules lined by high endothelial cells (HEV) when overlaid onto glutaraldehyde-fixed frozen sections of lymph nodes. This report describes the characteristics of TDL binding to HEV in unfixed frozen sections and compares this reactivity with that observed after fixing sections with different reagents. We found that TDL bound to unfixed HEV and that the pattern of adherence to such sections was identical to that observed when using glutaraldehyde-fixed tissue. Fixation of the sections with glutaraldehyde, however, enhanced the binding reaction. This effect was also observed when sections were treated with the diimidoester, dimethylsuberimidate (DMS) but not when methanol or formaldehyde was used. Since glutaraldehyde and DMS are each bifunctional cross-linking reagents, the results suggest that in vitro HEV adherence was facilitated under conditions in which the endothelial binding sites were present in an aggregated form.

A monoclonal antibody to viral glycoprotein blocks virus-immune effector T cells operating at H-2Dd but not at H-2Kd1

A particular monoclonal antibody that binds to the influenza virus HA molecule inhibits HA-specific thymus-derived lymphocytes mediating cytotoxicity in the context of H-2Dd but not of H-2Kd. Another monoclonal antibody blocks both sets of HA-specific effector T cells. This observation, together with related findings from other laboratories, is considered to support the idea that T cell recognition is directed against some association of viral and H-2 glycoproteins, as proposed in the original formulation of the "altered self" concept.

Inhibition of influenza-immune T cell effector function by virus-specific hybridoma antibody

The in vitro activity of influenza-specific cytotoxic T cells can be inhibited by incubation of the target cells with monoclonal anti-influenza antibodies. Hybridoma antibodies that bind to the virus HA inhibit the cytotoxic activity of TDL for the virus-infected target by as much as 80%, whereas these same antibodies never reduce splenic T cell function by more than 40%. This reflects the fact that TDL from anti-influenza strain A/WSN/33 (HON1) are highly subtype-specific, whereas splenic effector cells from the same mice are cross-reactive for target cells infected with heterologous influenza A viruses. These findings are discussed in the light of previous failures to block virus-immune T cell effector function with heterogeneous antisera produced in vivo, and are considered to favor the idea that at least some of the "virus-immune" T cells are indeed recognizing viral antigens.