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B R Ksander

Publications and source records attributed to B R Ksander.

At least 37 records · Page 2Linked to original sources
PubMed1997

Gene transfer of the CD80 costimulatory molecule into ocular melanoma cells using a novel episomal vector.

PURPOSE: The CD80 (B7.1) molecule, which is a necessary costimulatory signal for T-cell activation and proliferation, is a powerful inducer of antitumor immunity. In this study, primary human ocular melanoma cells were transfected with a novel vector (B45-Neo episomal vector) containing the complementary DNA (cDNA) for human CD80 to determine if this vector system is useful for stimulating CD8+ T cells. METHODS: Ocular melanoma cells were transfected with the B45-Neo episomal vector containing the cDNA for human CD80 and were positively selected in medium containing geneticin. The transcription of plasmid cDNA, plasmid copy number, and cell surface expression were determined on transfected tumor cell lines, and cloned tumor cells were obtained by limiting dilution techniques. The stability of CD80 expressed on tumor cells was determined after prolonged culture without geneticin and on irradiated cells. Autologous lymphocytes were restimulated with CD80+ tumor cells in the presence of recombinant interleukin-2 to determine whether CD8+ T cells were stimulated. RESULTS: CD80 was expressed on tumor cells transfected with the B45-Neo vector containing the cDNA for CD80. The level of CD80 expressed on different transfected tumor cell lines was heterogeneous and dependent on the plasmid copy number. High CD80 expression was observed on cloned tumor cells that possessed more than 520 plasmids per cell; intermediate levels were observed on tumor cells with approximately 240 to 520 plasmids. CD80+ ocular melanoma cells maintained a stable CD80 expression even after prolonged culture without geneticin, and on irradiated tumor cells. CD80 expressed on tumor cells was biologically functional and stimulated autologous CD8+ cells. CONCLUSIONS: The B45-Neo episomal vector induces stable expression of the CD80 costimulatory molecule on ocular melanoma cells. Our results indicate that this vector is suitable for experiments designed to genetically engineer ocular melanoma cells to stimulate CD8+ T cells.

B7-1 Antigen↗
PubMed1996

Role of donor-specific cytotoxic T cells in rejection of corneal allografts in normal and high-risk eyes.

Clinical ophthalmologists are highly successful in grafting allogeneic corneas onto healthy eye graft beds--only a small percentage are rejected. By contrast, a high percentage of allografts are rejected when grafted into vascularized or '"high-risk' recipient eyes. The following experiments test the hypothesis that donor-specific cytotoxic T cells mediate graft rejection in high-risk, but not normal, eyes. MHC plus minor histoincompatible C57BL/6 corneas were grafted orthotopically onto BALB/c mice. Healthy recipient eyes were trephined and served as normal graft beds; corneal vascularization was induced by penetrating sutures and these eyes served as 'high-risk' graft beds. Cytotoxic T cells were assayed at 2 and 8 weeks postgrafting using either draining cervical lymph nodes or spleen cells restimulated for 3 days with irradiated allogeneic splenic stimulator cells. As a positive control, donor-specific cytotoxic T cells were induced in mice immunized by subcutaneous injection of allogeneic spleen cells. A low percentage (only 50%) of corneal allografts were rejected when placed orthotopically onto normal healthy eyes. Donor-specific cytotoxic cells were not detected in the draining lymph nodes or spleens of mice that either accepted, or rejected their corneal graft. The failure to detect cytotoxic T cells was not due to anergy or the deletion of allospecific precursors of cytotoxic T cells. By contrast, 97% of corneal allografts were rejected from high-risk recipient eyes (no immune privilege). Donor-specific cytotoxic T cells were routinely detected in the draining lymph nodes of these mice and their appearance coincided with graft rejection. We conclude that allografts placed onto normal healthy eyes fail to induce donor-specific cytotoxic T cells. In the absence of specific cytotoxic T cells, other alloimmune effectors are less successful at mediating rejection. By contrast, allografts placed onto high-risk eyes induce donor-specific cytotoxic T cells, and all grafts are universally rejected. These results imply that immune privilege can protect corneal allografts from most effector mechanisms, except cytotoxic T cells.

Animals↗
PubMed1996

Minor H, rather than MHC, alloantigens offer the greater barrier to successful orthotopic corneal transplantation in mice.

Irrespective of HLA matching, a far higher proportion of human corneal allografts placed orthotopically in avascular corneal graft beds are accepted indefinitely, compared to other types of solid tissue allografts. However, many more corneal grafts are rejected if they are transplanted onto neovascularized recipient eyes. Using a murine model of orthotopic corneal transplantation in which grafts were placed in normal eyes, we have reported previously that grafts bearing minor H antigens alone are more likely to be rejected (approximately 50%) than are grafts displaying only MHC alloantigens (< 20%). Moreover, recipients of MHC plus minor H incompatible corneal grafts developed delayed hypersensitivity (DH) directed solely at minor H antigens. These studies have now been extended to include corneal grafts placed in neovascularized recipient eyes. Neovascularization was induced by placing sutures in the central cornea of one eye of BALB/c mice. Two weeks later corneas from C57BL/10 donors were grafted into these eyes. Rejection reactions were first apparent within 7 days and all grafts were destroyed by 14 days. Donor-specific DH responses were examined by injecting irradiated donor antigen-bearing spleen cells into the ear pinna. To distinguish DH directed at MHC versus minor antigens, some graft recipients were ear-challenged with BALB.B cells (donor MHC only), while other received B10.D2 cells (donor minor H only). Intense ear-swelling responses were evoked by B10.D2 cells, but not by BALB.B cells. These findings indicate that, for orthotopic corneal allografts, minor H antigens offer a more formidable barrier to graft acceptance than do MHC-encoded antigens. We speculate that this unexpected outcome may reflect a reduced level of MHC expression on corneal tissue. Moreover since the cornea lacks bone marrow derived dendritic cells, allorecognition by recipient T cells must occur via the indirect pathway, and in this situation minor H antigens may compete favorably with MHC antigens for processing and presentation by recipient antigen-presenting cells.

Animals↗
PubMed1995

Fate of orthotopic corneal allografts in eyes that cannot support anterior chamber-associated immune deviation induction.

PURPOSE: Corneal allografts placed in human eyes at high risk often fail, and immune rejection is thought to be a major pathogenic factor. To understand the immunologic factors responsible for rejection in this instance, the authors have created "high-risk" eyes in mice by inducing corneal neovascularization. The authors then examined the fate of orthotopic corneal grafts placed in these beds and assessed the development of donor-specific delayed hypersensitivity (DH) in recipient mice. METHODS: Three interrupted sutures were placed in the central cornea of recipient BALB/c mice to induce corneal neovascularization. Two weeks later, when corneal vessels occupied more than two quadrants of the cornea, mice received orthotopic corneal grafts from donor mice expressing alloantigens encoded by major and minor histocompatibility loci. Corneal allografts were evaluated by slit-lamp examination after grafting, and recipient mice were examined at the time of the rejection to determine whether they had acquired DH to alloantigens expressed on the corneal grafts. RESULTS: Compared to grafts placed in normal eyes, a much higher incidence of rejection was observed among corneal allografts placed in neovascularized eyes (96.7% versus 46.7%). Moreover, grafts in neovascularized beds were rejected much more swiftly (2 weeks versus > 3 to 4 weeks). Rejection of corneal allografts in high-risk eyes coincided temporally with development of intense donor-specific DH, and the specificity of this immune response was directed solely at minor H antigens (not major histocompatibility complex-encoded antigens) on the graft. CONCLUSIONS: These results indicate that eyes rendered high risk by virtue of corneal neovascularization fail to provide immune privilege for orthotopic corneal allografts. In this circumstance, the grafts rapidly induce intense donor-specific DH that is readily detectable within 2 weeks of engraftment, at which time the grafts are acutely and universally rejected. The recipient DH response is directed exclusively at minor H antigens on the graft, which is consistent with the view that neovascularization creates graft beds in which recipient antigen-presenting cells infiltrate the graft and carry antigenic information by lymphatics to draining lymph nodes. In this manner, anterior chamber-associated immune deviation is avoided, and potentially allodestructive DH is promoted.

Acute Disease↗
PubMed1994

Imposing deviant immunity on the presensitized state.

Delayed hypersensitivity (DH) is an important immune effector modality that successfully wards off intracellular pathogens and many parasites, but also causes immunopathogenic injury to vital tissues. Particularly in the eye, DH has devastating effects that can lead to blindness. Ags injected into the anterior chamber of the eye of naive mice elicit a deviant form of systemic immunity in which DH is selectively down-regulated. Expression of DH in this model system is curtailed by regulatory CD8+ T cells. At present, we have determined whether injection of Ag into the anterior chamber of eyes of specifically sensitized mice also impairs DH expression. Our results indicate that DH is blunted or eliminated in previously primed mice when heterologous proteins, retinal autoantigens, or minor histocompatibility Ags are injected into the anterior chamber. Suppression is achieved in this system by Ag-specific CD8+ T cells, and failed DH can be imposed on immunized mice by i.v. injections of peritoneal exudate cells pulsed with Ag in vitro in the presence of TGF-beta. Thus, the immune regulatory mechanisms that operate to protect the eye from immunogenic inflammation can be invoked in previously sensitized mice. In addition, tolerance could not be generated in presensitized mice by either i.v. injection of soluble Ag or painting of hapten on UVB-exposed skin. It seems that the strategies used by the eye to create a deviant state of immunity in the face of pre-existing conventional immunity may be unique.

Animals↗
PubMed1993

Incomplete activation of lymphokine-producing T cells by alloantigenic intraocular tumours in anterior chamber-associated immune deviation.

We have examined by limit dilution analysis the frequency of several types of DBA/2-specific precursor cells found in the draining lymph nodes of BALB/c mice following anterior chamber or subconjunctival inoculations of P815 tumour cells. Assays for precursors of cytotoxic T cells (pTc) and T-helper cells [interleukin-2 (IL-2)- and IL-4-producing cells] were conducted periodically during a 6-month interval after injection of tumour cells. The results indicate that nodes of both sets of recipients contained primed P815-specific CD8+ pTc that were detectable within 2 weeks of tumour implantation, and persisted throughout the 6-month observation period. Early after tumour inoculation, but not thereafter, these CD8+ cells also secreted Il-2. By contrast, only lymph nodes from mice that received P815 cells into the subconjunctival space contained CD4+ cells that secreted both IL-2 and IL-4; eventually, IL-4-secreting cells formed the vast majority of P815-specific CD4+ cells in these mice. Lymph nodes of mice that received P815 cells in the anterior chamber contained CD4+ T cells that were clonally expanded, and secreted IL-2, but not IL-4. These IL-2-secreting cells proved to be short-lived and were not present 6 months after inoculation. It is proposed that the IL-2- and IL-4-secreting T cells found in lymph nodes of subconjunctival tumour recipients are in vivo homologues of Th0 cells, that these cells can mediate delayed hypersensitivity responses, and that they are the forerunners of, or are themselves, memory T cells. These data indicate that the failure of mice that receive P815 tumour cells in the anterior chamber to display antigen-specific delayed hypersensitivity results from an inability to convert antigen-activated, IL-2-only-secreting CD4+ T cells (pTh) into Th0 cells. These findings also imply that mice with anterior chamber-associated immune deviation (ACAID) fail to develop memory CD4+ T cells.

Animals↗
PubMed1992

Local T helper cell signals by lymphocytes infiltrating intraocular tumors.

Tumor-infiltrating lymphocytes from mice bearing minor histoincompatible tumor cells in the anterior chamber (AC) or subconjunctival (SCon) space of the eye have been shown to contain large numbers of tumor-specific precursor cytotoxic T cells. Because SCon tumors eventually acquire directly cytotoxic, tumor-specific T cells and are rejected by their hosts and because AC tumors never acquire cytotoxic effector cells and are not rejected, we have examined tumor-infiltrating lymphocytes from both types of ocular tumors for the capacity to secrete lymphokines in response to in vitro stimulation with tumor cells. The results indicate that T "helper" cells were able to infiltrate both SCon and AC tumors. In the former, T cells capable of secreting IL-2 and IL-4 were found whereas in the latter only IL-2-secreting T cells were detected. These findings implicate a defect in local delivery of appropriate T cell help as the reason why AC tumors are not rejected. The failure of AC tumor-bearing mice to destroy their tumors correlates not only with defective delivery of local help but with a systemic inability to produce tumor-specific T cells that can secrete IL-2 and IL-4. Because these mice also generate down-regulatory T cells that suppress the expression of tumor-specific delayed hypersensitivity, they appear to have an immunologically mediated block in T helper cell differentiation which renders them unable to generate either T helper 1 or T helper 2 cells. This immunologic abnormality is discussed in terms of tumor rejection and the phenomenon of immunologic privilege.

Animals↗
PubMed1991

Infiltration and accumulation of precursor cytotoxic T-cells increase with time in progressively growing ocular tumors.

Precursors of cytotoxic T-cells (pTc) infiltrate P815 tumors growing progressively within the immunologically privileged anterior chamber (AC) of BALB/c mouse eyes, but directly cytotoxic T-cells cannot be detected in these eyes. To determine if the failure to reject these tumors is due to a relative inability of tumor-specific pTc to gain access to, or be retained by, the tumor-containing eye, we have assayed through time the frequency of pTc in eyes that received P511 tumor cells in the AC or subconjunctival space (SC; a site where the tumors are rejected). P511 tumor cells, a hypoxanthine-amethopterin-thymine medium-sensitive derivative of P815 cells, were selected for these studies because P511 tumor cells can be eliminated from in vitro lymphocyte cultures containing hypoxanthine-amethopterin-thymine medium, permitting us to make accurate estimates of pTc frequencies. To ensure that P511 cells are similar biologically and immunologically to P815 tumor cells, we demonstrated that both P511 and P815 cells form progressively growing tumors when injected into the AC of BALB/c eyes and that recipients of both tumor cell lines develop DBA/2-specific anterior chamber-associated immune deviation. Using cell suspensions harvested from eyes of mice bearing AC or SC P511 tumors, we found that tumor-specific pTc appeared first (day 8) in SC tumor-bearing eyes, compared to their appearance in AC tumor-bearing eyes (day 11). Thereafter, however, the number of pTc detected was significantly greater in eyes bearing progressively growing AC tumors than in SC tumor-injected eyes. The number and frequency of pTc we found in these eyes appeared to correlate directly with the size of the ocular tumor burden. We conclude that failure to reject P511 tumor from the AC can be ascribed neither to a quantitative deficiency in infiltrating tumor-specific pTc nor to an inability to retain pTc at the site. Our findings suggest that immune acceptance of allogeneic ocular tumor grafts may result from failure of infiltrating pTc to differentiate terminally in situ into cytotoxic effector cells.

Animals↗
PubMed1991

Characterization of specific T helper cell activity in mice bearing alloantigenic tumors in the anterior chamber of the eye.

P815 tumor cells injected in the anterior chamber (AC) of eyes of BALB/c mice elicit anterior chamber-associated immune deviation (ACAID) whereby delayed-type hypersensitivity (DTH) responses to the tumor-associated antigens are suppressed, precursors of cytotoxic T cells are clonally expanded but not terminally differentiated, and levels of tumor-specific serum antibodies are elevated. These results imply the presence of unique helper T (Th) cell functions in these animals. To identify and describe these cells, we first determined the presence of antigen-activated lymphocytes in AC tumor-bearing mice, as well as mice that received tumor cells subconjunctivally (SC), as measured by proliferative responses of lymphocytes from draining lymph nodes and spleens. In addition, we examined the lymphokine secretion profiles [interleukin (IL) 2, IL 4] of antigen-responsive lymph node and spleen cells in limiting dilution analysis. We found that lymphoid organs of mice primed by the SC route contained high frequencies of antigen-reactive CD4+ cells that secreted IL 2 only, or IL 2 plus IL 4. In addition, IL 2-secreting CD8+ cells were found. Alternatively, the lymphoid organs of mice receiving AC inoculations of P815 cells contained CD4+ as well as CD8+ cells that secreted IL 2 after antigen stimulation. However, no IL 4-secreting cells were found. According to a recent model of differentiation of CD4+ T cells, precursors of Th cells (that secrete IL 2 alone) differentiate into Th0 cells that can secrete IL 2, IL 4 and IFN-gamma. These cells further differentiate into Th1 cells and Th2 cells that secrete IL 2 or IL 4, respectively. We interpret the absence of IL 4-secreting CD4+ cells in AC tumor bearing mice to mean that in these mice precursor Th cells are unable/prevented from differentiating into Th0 cells.

Animals↗
PubMed1991

Termination of immune privilege in the anterior chamber of the eye when tumor-infiltrating lymphocytes acquire cytolytic function.

Minor H incompatible P815 tumor cells form progressively growing intraocular tumors when injected into the anterior chamber of eyes of BALB/c mice (an immunologically privileged site), but these tumor cells are promptly rejected when injected into the subconjunctival space. In both circumstances, the tumor inoculation site acquires significant numbers of DBA/2-specific precursor cytotoxic T cells (pTc) but only at the subconjunctival site do fully functional cytotoxic T cells (Tc) emerge, and their emergence coincides temporally with rejection of the tumor graft. In the present study, we wished to determine whether pTc can differentiate into Tc within the anterior chamber of the eye and whether the failure of BALB/c mice to reject intraocular P815 tumors is related to this putative block in pTc differentiation. It was previously shown that P815 tumor cells injected into the eyes of MHC-incompatible C57BL/6 mice are able to grow transiently within the anterior chamber and that they are eventually rejected. We have examined the local cytotoxic T cell responses during and after the transient phase of immune privilege that is extended to MHC-incompatible tumor grafts in eyes of C57BL/6 mice. Our results indicate that termination of immune privilege (rejection of the tumor implant) coincides with the detection of fully functional Tc within the tumor-containing eye. Circumstantial evidence suggests that these tumors are infiltrated with DBA/2-specific pTc during the phase of progressive tumor growth and that it is these infiltrating cells that differentiate in oculi into the Tc that effect graft rejection. These findings support the hypotheses that immune privilege in the anterior chamber of the eye is an actively maintained process that suppresses terminal differentiation of pTc and that privilege is abolished if conversion of pTc to Tc is accomplished.

Animals↗
PubMed1991

Studies of tumor-infiltrating lymphocytes from a human choroidal melanoma.

Cell suspensions prepared enzymatically from an ocular choroidal melanoma were cultured in vitro in an effort to generate (1) melanoma tumor cell lines and (2) tumor-infiltrating lymphocytes cytotoxic for ocular melanoma cells. Even though histologic study of the tumor did not show "significant" infiltrating bone marrow-derived cells, lymphocytes were generated readily in cultures to which interleukin-2 was added. Phenotypic analysis of the cultured lymphocytes indicated that T-cells, natural killer (NK) cells, and lymphokine-activated killer (LAK) cells were present. Moreover, functional studies of the cultured lymphocytes revealed NK activity, LAK activity, and most importantly, tumor antigen-specific cytotoxic T-cell activity. It was concluded that it is possible to obtain tumor cell lines and tumor-infiltrating lymphocytes from ocular tumors, both of which would be required if cellular immunotherapy of ocular tumors is contemplated. In addition, these results indicate that ocular melanomas can express unique tumor-specific antigens and that the immune system of a patient with such an ocular tumor can perceive these tumor antigens because antigen-specific precursor cytotoxic T-cells were present in the tumor-containing eye at the time of enucleation. The theoretic and therapeutic implications of these findings are discussed.

Adult↗
PubMed1990

Failure of infiltrating precursor cytotoxic T cells to acquire direct cytotoxic function in immunologically privileged sites.

Minor H incompatible P815 tumor cells inoculated into the anterior chamber (AC) of the eyes of BALB/c mice grow progressively, revealing this to be an immunologically privileged site. By contrast, a similar inoculation of tumor cells is rapidly rejected from nonprivileged ocular sites (subconjunctiva). Mice with progressively growing AC-tumors and those that reject their ocular subconjunctiva tumors both have expanded clones of tumor-specific cytotoxic precursor cells (pTc) in their spleens and cervical lymph nodes. In an effort to determine why the expanded pool of primed pTc is unable to effect rejection of AC intraocular tumors, we have examined the susceptibility of the tumor cells growing within the immunologically privileged AC to lysis by cytotoxic T cells and the cytotoxic function of tumor-infiltrating lymphocytes. P815 tumor cells extracted from intraocular tumors and P815 cells maintained in routine tissue culture are equally susceptible to lysis when exposed in vitro to fully differentiated, DBA/2-specific cytotoxic T cells. Thus, progressively growing tumor cells within the AC are not insensitive to immune-mediated lysis by cytotoxic T cells. We have been able to harvest significant numbers of DBA/2-specific pTc from these same intraocular tumors. When the tumor-infiltrating lymphocytes are driven in vitro with exogenous IL-2, they acquire the capacity to lyse specifically P815 tumor cells. However, no evidence of fully cytotoxic, tumor-specific T cells was found among lymphocytes harvested from intraocular tumors, i.e., when the harvested cells were tested immediately for cytolytic activity. Inasmuch as we have reported that directly cytotoxic T cells are present during tumor rejection at nonimmunologically privileged ocular sites, such as the subconjunctival space, we conclude that progressive growth of P815 tumor cells within the anterior chamber is due in part to a failure of infiltrating pTc to differentiate in situ into fully functional cytotoxic effector cells.

Animals↗
PubMed1989

Recovery of activated cytotoxic T cells from minor H incompatible tumor graft rejection sites.

In this study we determined whether minor H-specific cytotoxic T cells and their precursors (pTc) are present at the site of rejection of minor H disparate tumor allografts. Lymphocytes were retrieved from eyes of BALB/c mice that received subconjunctival injections of minor H-incompatible P815 tumor cells. The lymphocytes were then assayed for direct cytotoxic activity as well as precursor frequency by limiting dilution. Similar assays were conducted on cells obtained from the draining lymph nodes and from the spleen. As expected, tumor rejection was accompanied by significant clonal expansion of minor H-specific pTc within the draining lymph node and the spleen. A correspondingly high frequency of pTc was also detected at the graft site. More importantly, fully functional cytotoxic T cells were recovered from the tumor graft site during rejection, but no similarly active cells were found in either the draining nodes or spleen. We conclude that, after Ag stimulation, pTc are generated in draining central lymphoid compartments. From this generative site, the precursor cells then disseminate systemically, gradually reaching and infiltrating the tumor graft site. A further activation step, dependent upon Ag and T cell help, permits these cells to mature into fully active cytotoxic cells which can then effect tumor rejection. We propose that the terminal stage(s) of pTc activation is promoted by lymphokines released locally from TDH cells that are also generated during the alloimmune response and simultaneously infiltrate the site.

Animals↗
PubMed1989

Immune privilege to MHC-disparate tumor grafts in the anterior chamber of the eye. I. Quantitative analysis of intraocular tumor growth and the corresponding delayed hypersensitivity response.

It has been suggested that immune privilege that is extended to tissues placed in the anterior chamber of the eye may not be absolute, implying that a form of transient privilege may exist. We have studied the extent of immune privilege for histoincompatible tumor cells in the anterior chamber of the eye by using a modification of the limiting dilution analysis technique to quantitate the magnitude of tumor growth. It was found that immune privilege was absolute for minor-histoincompatible tumor cells inoculated into the anterior chamber of the eye. In this circumstance, tumor growth was unrestricted and quantitatively equivalent to tumor growth observed in the eyes of syngeneic mice. By contrast, immune privilege for MHC-incompatible tumor cells inoculated into the anterior chamber proved to be present, but transient. MHC-incompatible tumors grew within the anterior chamber of the eye during the first 12 days in a manner quantitatively indistinguishable from minor H tumors. However, these tumors were ultimately rejected, although survival of the tumor cells was prolonged and the maximum tumor mass achieved was larger than that observed for similar tumors injected subconjunctivally (a nonprivileged site). Early successful tumor growth was associated with impaired, alloantigen-specific delayed hypersensitivity, whereas rejection of the tumor coincided with the systemic emergence of specific DH. These results support the conclusion that immune privilege in the anterior chamber of the eye may be transient, rather than absolute, and that the critical determinant is whether a systemic state of tumor-specific DH can be affected.

Animals↗
PubMed1989

Analysis of cytotoxic T cell responses to intracameral allogeneic tumors.

Injection of P815 mastocytoma tumor cells into the anterior chamber (AC) of BALB/c mice results in progressively growing intraocular tumors, whereas injection of the same dose of tumor cells subcutaneously results in rapid rejection of the tumor. Previous results indicated that AC P815 inoculation results in an unorthodox immune response characterized by suppressed delayed hypersensitivity, elevated antibody levels and priming for cytotoxic T lymphocyte (CTL) activity. Since mice inoculated in the AC with P815 cells display progressively growing intraocular tumors in spite of the fact they are primed for CTL activity, we examined whether the differential tumor growth patterns between AC and SC inoculation are the result of an aberrant and weak cytotoxic response in the former. We analyzed the lytic activity, target specificity and frequency of cytotoxic precursors and effector cells in the spleen following AC and SC inoculation of P815 cells. Our results indicate that both AC and SC routes of P815 inoculation generate splenic CTL effector cells with equivalent lytic activity for P815 tumor target cells. These effectors are highly specific for P815 cells and do not lyse third-party EL-4 targets. Analysis of the frequency of cytotoxic T cell precursors (pTc) in the spleen and lymph nodes of animals that received AC and SC injections revealed that both routes generated comparable pTc frequencies. Thus, tumor cells placed in the anterior chamber are capable of generating a full complement of cytotoxic precursors and effectors, that are equivalent to those that are generated following SC injection. Therefore, the progressive growth of the tumor in the eye cannot be attributed to a defect in the tumor-specific CTL response.

Animals↗