Adoptive immunity

Abstract: The ability of CD4+ and CD8+ T cells to adoptively immunize mice against Chlamydia trachomatis infection of the mouse genital tract was studied. Adoptive transfer experiments were performed with splenic CD4+ or CD8+ T cells obtained from mice following resolution of a primary genital tract infection and after a secondary chlamydial challenge. The results show that donor CD4+ T cells, but not CD8+ T cells, obtained from mice following resolution of a primary infection or after secondary challenge were effective in transferring significant antichlamydial immunity to the genital tracts of naive animals. The lymphokine profiles in the culture supernatants of proliferating Chlamydia-specific CD4+ T cells obtained from mice following resolution of a primary infection and after secondary challenge were assayed by an enzyme-linked immunoadsorbent assay. Protective CD4+ T cells restimulated in vitro secreted interleukin 2, gamma interferon, and interleukin 6, lymphokine profiles characteristic of both Th1- and Th2-like responses. Resting CD4+ T cells obtained from mice 4 months following resolution of a primary infection were also capable of conferring significant levels of adoptive protective immunity to naive mice. These findings support an important role for CD4+ T cells in acquired immunity to chlamydial infection of the genital tract and indicate that protective CD4+ immune responses in this model are relatively long lived.

Abstract: A method was described for the generation of cells from tumor-bearing mice; these cells were capable of exhibiting significant antitumor reactivity when adoptively transferred into tumor-bearing hosts. Tumor cell suspensions from a variety of tumors were able to be separated using enzymatic techniques and they were cultured in medium containing recombinant interleukin-2. Activated infiltrating lymphocytes within these tumors expanded; and, by 6-8 days after initiation of culture, lymphocytes predominated and were able to grow to large numbers. The adoptive transfer of these tumor-infiltrating lymphocytes (TILs) made possible mediation of the reduction of established 3-day pulmonary micrometastases from 5 of 7 tumors tested, including two 3-methylcholanthrene (CAS: 56-49-5)-induced sarcomas, one 1,2-dimethylhydrazine (CAS: 540-73-8)-induced colon carcinoma, and the B16 melanoma, all in C57BL/6 mice, as well as the 1660 bladder carcinoma in BALB/c mice. Approximately 2-4 X 10(6) transferred cells were capable of totally eliminating 3-day established metastases. These cells were thus 50 to 100 times more effective than lymphokine-activated killer cells in reducing established metastases; however, they could not be generated from all tumors. The concomitant administration of recombinant interleukin-2 enhanced, by approximately fivefold, the in vivo activity of these cells. The specificity of action of TILs in vivo was different from that determined by classic amputation rechallenge experiments. The tumor-infiltrating lymphocytes that developed this antitumor reactivity appeared to be Thy-1+ and did not bear the asialo GM1 antigen. The potent antitumor effect of these TILs, when transferred in vivo to tumor-bearing hosts, raises the possibility of utilizing similar approaches for the isolation and therapeutic use of lymphocytes with antitumor reactivity from human tumors.

Abstract: Recent increases in knowledge of cellular immunology, combined with developments in biotechnology, have provided new opportunities for the development of immunotherapies for the treatment of cancer in humans. One approach to therapy is that of adoptive immunotherapy, that is, the transfer to the tumor bearing host of lymphoid cells with antitumor reactivity that can mediate antitumor responses. Several lymphocyte subpopulations have now been identified that may be suitable for use in adoptive immunotherapy. Resting lymphocytes incubated in interleukin-2 (IL-2) give rise to lymphokine activated killer (LAK) cells that can lyse malignant cells, but not normal cells. Clinical studies in patients with advanced cancer have revealed that treatment with high dose IL-2 alone or in combination with LAK cells can mediate the complete or partial regression of cancer in selected patients. Other approaches are currently undergoing investigation, including the adoptive transfer of tumor infiltrating lymphocytes, which, in animal models, have antitumor reactivity 50-100 times more potent than do LAK cells. Other new approaches to immunotherapy include the use of combination of lymphokines, such as the use of tumor necrosis factor or alpha interferon in conjunction with IL-2. The availability of recombinant lymphokines that provide large amounts of biologically active materials can hopefully lead to the development of effective new therapies for cancer in humans.

Abstract: BACKGROUND AND OBJECTIVE: Cell therapy can be considered as a strategy aimed at replacing, repairing, or enhancing the biological function of a damaged tissue or system by means of autologous or allogeneic cells. There have been major advances in this field in the last few years. This has prompted the Working Group on Hematopoietic Cells to examine the current utilization of this therapy in clinical hematology. EVIDENCE AND INFORMATION SOURCES: The method employed for preparing this review was that of informal consensus development. Members of the Working Group met three times, and the participants at these meetings examined a list of problems previously prepared by the chairman. They discussed the single points in order to reach an agreement on different opinions and eventually approved the final manuscript. Some of the authors of the present review have been working in the field of cell therapy and have contributed original papers in peer-reviewed journals. In addition, the material examined in the present review includes articles and abstracts published in journals covered by the Science Citation Index and Medline. STATE OF THE ART: Lymphokine-activated killer (LAK) and tumor-infiltrating lymphocytes (TIL) have been used since the '70s mainly in end-stage patients with solid tumors, but the clinical benefits of these treatments has not been clearly documented. TIL are more specific and potent cytotoxic effectors than LAK, but only in few patients (mainly in those with solid tumors such as melanoma and glioblastoma) can their clinical use be considered potentially useful. Adoptive immunotherapy with donor lymphocyte infusions has proved to be effective, particularly in patients with chronic myeloid leukemia, in restoring a state of hematologic remission after leukemia relapse occurring following an allograft. The infusion of donor T-cells can also have a role in the treatment of patients with Epstein-Barr virus (EBV)-induced post-transplant lymphoproliferative disorders. However, in this regard, generation and infusion of donor-derived, virus specific T-cell lines or clones represents a more sophisticated and safer approach for treatment of viral complications occurring in immunocompromised patients. Whereas too few clinical trials have been performed so far to draw any firm conclusion, based on animal studies dendritic cell-based immunotherapy holds promises of exerting an effective anti-tumor activity. Despite leukemic cells not being immunogenic, induction on their surface of co-stimulatory molecules or generation of leukemic dendritic cells may induce antileukemic cytotoxic T-cell responses. Tumor cells express a variety of antigens and can be genetically manipulated to become immunogenic. The main in vitro and in vivo functional characteristics of marrow mesenchymal stem cells (MSCs) with particular emphasis on their hematopoietic regulatory role are reviewed. In addition, prerequisites for clinical applications using culture-expanded mesenchymal cells are discussed PERSPECTIVES: The opportuneness of using LAK cells or activated natural killer (NK) cells in hematologic patients with low tumor burden (e.g. after stem cell transplantation) should be further explored. Moreover the role of new cytokines in enhancing the antineoplastic activity of NK cells and the infusion of selected NK in alternative to CTL for graft versus leukemia (GVL) disease (avoiding graft versus host disease (GvHD) seems very promising. Separation of GVL from GvHD through generation and infusion of leukemia-specific T-cell clones or lines is one of the most intriguing and promising fields of investigations for the future. Likewise, strategies devised to improve immune-reconstitution and restore specific anti-infectious functions through either induction of unresponsiveness to recipient alloantigens or removal of alloreactive donor T-cells might increase the applicability and success of hematopoietic stem cell transplantation. (ABSTRACT TRUNCATED)