Administration Of anti-CD4 Antibody Research Articles

TCR Repertoire Analysis Reveals Mobilization of Novel CD8+ T Cell Clones Into the Cancer-Immunity Cycle Following Anti-CD4 Antibody Administration.

Depletion of CD4+ cells using an anti-CD4 monoclonal antibody (anti-CD4 mAb) induces the expansion of tumor-reactive CD8+ T cells and strong antitumor effects in several murine tumor models. However, it is not known whether the anti-CD4 mAb treatment activates a particular or a broad spectrum of tumor-reactive CD8+ T cell clones. To investigate the changes in the TCR repertoire induced by the anti-CD4 mAb treatment, we performed unbiased high-throughput TCR sequencing in a B16F10 mouse subcutaneous melanoma model. By Inter-Organ Clone Tracking analysis, we demonstrated that anti-CD4 mAb treatment increased the diversity and combined frequency of CD8+ T cell clones that overlapped among the tumor, draining lymph node (dLN), and peripheral blood repertoires. Interestingly, the anti-CD4 mAb treatment-induced expansion of overlapping clones occurred mainly in the dLN rather than in the tumor. Overall, the Inter-Organ Clone Tracking analysis revealed that anti-CD4 mAb treatment enhances the mobilization of a wide variety of tumor-reactive CD8+ T cell clones into the Cancer-Immunity Cycle and thus induces a robust antitumor immune response in mice.

Spleen Plays an Important Role in Maintaining Tolerance After Removal of the Vascularized Heart Graft

This study addresses the question of the mechanism for maintaining tolerance to donor alloantigen in the absence of antigen and the role of secondary lymphoid tissues. Depleting anti-CD4 antibody administration in conjunction with allogeneic heart transplantation generates donor-specific operational tolerance. Primary C57BL/6 heart grafts were transplanted into the neck cavity of the anti-CD4 antibody pretreated C3H/He mice. At day 50, functioning heart grafts were removed from tolerant mice. At day 100, a secondary C57BL/6 or a third-party heart was transplanted into the abdomen. Anti-CD4 antibody therapy induced CD4CD25 regulatory T cells by 50 days after transplantation, as depleting anti-CD25 treatment in tolerant mice abrogated graft prolongation when spleen leukocytes were adoptively transferred to syngeneic mice. Tolerance was maintained by CD4CD25 regulatory T cells via a CTLA-4 signal at 100 days, even after removal of the primary graft at day 50. Administration of anti-CD25 antibody immediately after removal of the primary graft did not break tolerance, as five out of six second allografts transplanted at day 100 were accepted. Anti-CD25 antibody therapy in conjunction with splenectomy, but not thymectomy, immediately after removal of primary heart grafts at day 50 broke tolerance at day 100; all allografts were rejected. The spleen is important in maintaining CD4CD25 regulatory T cells after primary allograft removal.

Immune Response to Adenovirus-Delivered Antigens Upregulates Utrophin and Results in Mitigation of Muscle Pathology inmdxMice

The upregulation of endogenous utrophin in skeletal muscle may lead to a new approach to the treatment of Duchenne muscular dystrophy (DMD). We found that injection of an E1, E3-deleted adenovirus vector expressing beta-galactosidase (beta-Gal) or green fluorescent protein (GFP) into the skeletal muscle of neonatal dystrophin-deficient mdx mice alleviated dystrophic pathology. In the adenovirus-infected muscles, an evaluation of sarcolemma stability showed low permeability and immunohistochemistry revealed utrophin upregulation at the extrasynaptic sarcolemma of mature muscle fibers. This utrophin upregulation was concomitant with endomysial cellular infiltration from a host immune reaction. There was no evidence of active muscle regeneration. In normal C57BL/10 mice, utrophin was also upregulated in adenovirus-injected skeletal muscles, where upregulated utrophin often coexisted with dystrophin. FK506 and anti-CD4 antibody administration decreased utrophin expression in adenovirus-injected mdx muscles and prevented the dystrophic phenotype from being mitigated, suggesting that an immune reaction is involved in utrophin upregulation. This is the first report demonstrating the improvement of the dystrophic phenotype as a result of the acquired overexpression of endogenous utrophin. Our findings provide an important clue to understanding the mechanism of utrophin expression and the development of an effective treatment for DMD.

Ambiguous role of interleukin-12 in Yersinia enterocolitica infection in susceptible and resistant mouse strains.

Endogenous interleukin-12 (IL-12) mediates protection against Yersinia enterocolitica in C57BL/6 mice by triggering gamma interferon (IFN-gamma) production in NK and CD4+ T cells. Administration of exogenous IL-12 confers protection against yersiniae in Yersinia-susceptible BALB/c mice but exacerbates yersiniosis in resistant C57BL/6 mice. Therefore, we wanted to dissect the different mechanisms exerted by IL-12 during Yersinia infections by using different models of Yersinia-resistant and -susceptible mice, including resistant C57BL/6 mice, susceptible BALB/c mice, intermediate-susceptible wild-type 129/Sv mice, 129/Sv IFN-gamma-receptor-deficient (IFN-gamma R-/-) mice and C57BL/6 tumor necrosis factor (TNF) receptor p55 chain-deficient (TNFR p55-/-) mice. IFN-gamma R-/- mice turned out to be highly susceptible to infection by Y. enterocolitica compared with IFN-gamma R+/+ mice. Administration of IL-12 was protective in IFN-gamma R+/+ mice but not in IFN-gamma R-/- mice, suggesting that IFN-gamma R-induced mechanisms are essential for IL-12-induced resistance against yersiniae. BALB/c mice could be rendered Yersinia resistant by administration of anti-CD4 antibodies or by administration of IL-12. In contrast, C57BL/6 mice could be rendered more resistant by administration of transforming growth factor beta (TGF-beta). Furthermore, IL-12-triggered toxic effects in C57BL/6 mice were abrogated by coadministration of TGF-beta. While administration of IL-12 alone increased TNF-alpha levels, administration of TGF-beta or TGF-beta plus IL-12 decreased both TNF-alpha and IFN-gamma levels in Yersinia-infected C57BL/6 mice. Moreover, IL-12 did not induce toxicity in Yersinia-infected TNFR p55-/- mice, suggesting that TNF-alpha accounts for IL-12-induced toxicity. Taken together, IL-12 may induce different effector mechanisms in BALB/c and C57BL/6 mice resulting either in protection or exacerbation. These results are important for understanding the critical balance of proinflammatory and regulatory cytokines in bacterial infections which is decisive for beneficial effects of cytokine therapy.

Experimental hypersensitivity pneumonitis: effect of Thy1.2+ and CD8+ cell depletion.

We previously demonstrated that recipient CD4+ cells are necessary for expression of adoptive murine experimental hypersensitivity pneumonitis (EHP). In contrast, the acute inflammatory response to intratracheal (i.t.) administration of Micropolyspora faeni (direct EHP) is not CD4+ cell dependent (Am. J. Respir. Crit. Care Med. 1994;149:1286-1294). To further characterize the cells responsible for development of pulmonary inflammation in recipient animals, we depleted recipients of either Thy1.2+ or CD8+ cells before transfer of M. faeni-sensitized cultured C3H/HeJ spleen cells and i.t. challenge with M. faeni. We used the same depletion technique to determine the contribution of these cells to the pulmonary response to i.t. M. faeni in animals that did not receive cultured cells (direct EHP). The nature and extent of pulmonary inflammatory changes in these animals were assayed either 4 d after i.t. challenge with M. faeni in adoptive EHP or 2 d after i.t. challenge with M. faeni in direct EHP. We also tested the hypothesis that our previously demonstrated ablation of adoptive EHP caused by administration of anti-CD4 antibody was due to depletion of recipient CD4+ cells by allowing recovery of recipient CD4+ cells of anti-CD4-treated animals before i.t. challenge. In addition, we allowed Thy1.2+ cell recovery of anti-Thy1.2-treated animals before i.t. challenge. Cultured M. faeni-sensitized spleen cells could adoptively transfer EHP to animals treated with an irrelevant antibody or PBS. Depletion of Thy1.2+ but not CD8+ cells ablated the ability of recipient animals to express adoptive EHP. Direct EHP was not affected by depletion of Thy1.2+ or CD8+ cells.(ABSTRACT TRUNCATED AT 250 WORDS)

A novel function of islet-derived CD8 +T cells in initiating and developing autoimmune insulin-dependent diabetes mellitus in non-obese diabetic (NOD) mice

Accumulated studies revealed that CD4 +T cells were initially required for diabetes in NOD mice, whereas interaction of CD4 +T/CD8 +T cells is not fully understood. To address this question, we established islet-derived CD4 +T cells and CD8 +T cells from NOD mice. One NOD neonate that received CD4 +T cells developed diabetes and insulitis with CD8 +T cells. Administration of cyclophosphamide to non-diabetic recipients accelerated the development of diabetes, while none of the mice with anti-CD8 antibody did so. Similarly, it was observed that neonates that received islet-derived CD8 +T cells developed diabetes and obvious insulitis mainly with CD4 +T cells. Administration of anti-CD4 antibody with transfer of CD8 +T cells inhibited insulitis. These results imply that CD8 +T cells function as an initial element to recruit CD4 +T cells to islets as well as a final effector.

Treatment of myasthenia gravis with anti‐CD4 antibody

We treated a patient with severe myasthenia gravis with a chimeric (murine/human) anti-CD4 monoclonal antibody (cM-T412) for 7 days and followed the therapeutic effect by standardized muscle function tests, single-fiber electromyography, and immunologic examinations of disease-specific B- and T-cell functions. Clinical and electrophysiologic improvement began within 4 days, lasted for 3 months, and was maximal between days 16 and 58. The CD4+ lymphocytes decreased to a minimum of 80 cells per microliters of peripheral blood, recovered slowly during the first year of follow-up, and did not correlate with changes in disease severity. T-cell stimulation by human acetylcholine receptor was abolished by the treatment but became detectable at the time of worsening of symptoms. The concentration of acetylcholine receptor antibodies in serum was not decreased by the treatment. The results suggest that anti-CD4 antibody administration could be effective in the treatment of severe myasthenia gravis and indicate that acetylcholine receptor-specific T lymphocytes might contribute to the disturbed neuromuscular transmission in the disease.

The role of CD4 cells in protective immunity to Brugia pahangi

The BALB/c mouse immunized sub-cutaneously (s.c.) with 45 kRad attenuated third stage larvae (L3) of the lymphatic filarial nematode Brugia pahangi is strongly immune to a challenge infection (75-100% reduction in recovery at day six post challenge). Analysis of spleen cell supernatants from immunized mice re-stimulated in vitro, with parasite antigen or the non specific T cell mitogen Con-A reveals a cytokine profile (IL-4, IL-5 and IL-9) which indicates that the Th2 subset of CD4 cells has been expanded. In an attempt to formally prove a critical role for CD4 cells in immunity in this model system, immunized mice were given either anti-CD4 or anti-CD8 neutralizing antibodies. Administration of anti-CD4 antibody had a significant and detrimental effect on the immune response whereas anti-CD8 antibody had a negligible effect on immunity. The efficacy of antibody in neutralizing their target cells was determined by fluorescence activated cell sorting analysis (FACS). Spleen cells from anti-CD4 treated immunized mice, when re-stimulated with parasite antigen had a significantly reduced potential to secrete IL-4, IL-5 and IL-9 in vitro and serum from these mice had reduced levels of parasite specific IgG and IgE. These results demonstrate a critical role for CD4 T cells in host protective immunity to B. pahangi in vivo and strongly suggest that some component of the Th2 response plays an important role in the immune response elicited in this model system.

Anti-CD4 monoclonal antibody administration in renal transplanted patients

Administration of anti-CD4 antibodies in rodents was shown to prevent or to reverse spontaneous or experimentally induced autoimmune diseases and to delay organ or skin allograft rejection. Some anti-human CD4 antibodies were shown to be immunosuppressive when injected in monkeys. BL4, and IgG2a anti-human CD4 murine monoclonal antibody, which binds to an epitope located between the two N-terminal domains of the CD4 molecule, was administered to 12 recipients of a renal cadaver allograft, in association with azathioprine (2.5 mg/kg/day) and prednisolone (1 mg/kg/day). Treatment was started 1 day after transplantation and was discontinued after 3 to 14 days (median 5 days). Infusion of 10 or 15 mg of BL4 over 1 hr induced a selective but transient CD4 + lymphocytopenia. The lack of clinical side effect was remarkable. Acute rejection occurred in 4 out of 12 treated patients. Antibody response to BL4 3 weeks after completion of the treatment was demonstrated in only one patient. Residual antibody concentrations in serum, 24 hr after infusion, ranged from 0.1 to 0.5 μg/ml, that is below the concentration required to achieve 50% inhibition of allogenic mixed lymphocyte reaction in vitro (1–10 μg/ml) or to saturate CD4 binding sites (5–10 μg/ml). Rapid degradation and dissociation of cell bound BL4 contributed to the failure to achieve high residual serum levels of the antibody.