TL antigen as a transplantation antigen recognized by TL-restricted cytotoxic T cells

In contrast to broadly expressed classical class I antigens of the major histocompatibility complex, structurally closely related TL antigens are expressed in a highly restricted fashion. Unlike classical class I antigens, TL antigens are not known to be targets of cytotoxic T cells or to mediate graft rejection. Whereas classical class I antigens function as antigen-presenting molecules to T cell receptors (TCR), the role of TL is yet to be defined. To elucidate the function of TL, we have derived transgenic mice expressing TL in most tissues including skin by introducing a TL gene, T3b of C57BL/6 mouse origin, driven by the H-2Kb promoter. By grafting the skin of transgenic mice, we demonstrate that TL can serve as a transplantation antigen and mediate a TCR-alpha/beta+ CD8+ cytotoxic T cell response. This T cell recognition of TL does not require antigen presentation by H-2 molecules. Furthermore, we show that C57BL/6 F1 mice develop CD8+ T cells that are cytotoxic for C57BL/6 TL+ leukemia cells, providing further support for the concept that aberrantly expressed nonmutated proteins such as TL can be recognized as tumor antigens.

Long-term survival of orthotopic Lewis liver grafts in Wistar Furth rats. Elimination or inactivation of effector CTL and altered antigenicity as possible reasons for tolerance

After orthotopic transplantation of rat livers from Lewis (LEW) donors into Wistar Furth (WF) recipients, a rejection response occurs 2 weeks after transplantation, followed by indefinite survival of the transplant. Spleen cells from WF rats bearing long-term LEW liver grafts responded in MLR and CML assays like spleen cells from normal WF rats after in vitro stimulation with mitomycin C-treated LEW spleen cells, but did not generate CTL after stimulation with paraformaldehyde-treated LEW spleen cells. Transient damage to the long-term grafted livers was induced by inoculation of recipients with homogenized normal LEW liver. CD8+ CTL were detected in the spleen at the time of this liver damage. These findings indicate that CTL precursors are present in WF rats bearing LEW liver transplants. These CTL precursors are capable of differentiating into effector CTL in vitro and in vivo in response to donor antigen. However, once generated, effector CTL in WF rats are eliminated or become unresponsive to the transplanted LEW liver. Homogenized LEW liver from grafted donors did not induce transient liver damage when inoculated into recipient WF rats bearing LEW liver transplants. The demonstration of large amounts of antibody bound to either parenchymal or nonparenchymal cells in the donor graft suggests that reduction (or loss) of antigenicity could also be responsible for the inability of LEW liver to elicit an immune response in WF-recipient rats. Thus, elimination or inactivation of effector CTL and altered antigenicity could both be responsible for maintaining tolerance after allogeneic liver transplantation.

Magnetic resonance imaging of oral and maxillofacial angiomas

Eleven patients with oral and maxillofacial angiomas (seven hemangiomas and four lymphangiomas) were evaluated with magnetic resonance imaging using a 0.2-T permanent system and spin-echo pulse sequences. These lesions typically had signal intensities that were iso T1-weighted, similar to muscle, and high T2-weighted, greater than subcutaneous fat. Nine tumors had well- or relatively well-defined margins, and seven cases had curvilinear structures of low signal intensities in the masses on T2-weighted images. It was impossible to distinguish hemangiomas from lymphangiomas on MR images. Our experience suggested that most angiomas of oral and maxillofacial regions present special characteristics on magnetic resonance images. It is thought that information obtained with magnetic resonance images can contribute significantly to the evaluation of the extent of these lesions.

Stafne's bone cavity. Classification based on outline and content determined by computed tomography

Fifteen cases (16 concavities) of the so-called "Stafne's bone cavity" were investigated with the use of computed tomography. The sizes, bony outlines, and contents were analyzed on axial images. In all cases, computed tomography clearly demonstrated the concavities on the lingual surface of the mandible. There were no empty concavities. The bony outlines and contents were divided into three types. The concavities with a portion of submandibular gland as a content were larger than those with other contents. Four of six concavities not extending to the buccal cortical plate were filled solely with fat tissue, whereas all concavities with expansion of the buccal cortical plate contained submandibular gland.

Roles of CD8+ and CD4+ cells on lethal graft-versus-host disease in nude mice

Roles of CD8+ and CD4+ cells on lethal graft-versus-host disease (GVHD) were investigated. Injection of spleen cells from C57BL/6 (B6) female mice into (BALB/c x B6)F1 nu/nu female mice caused subacute lethal GVHD (survival: 10-50 days). Injection of anti-Lyt-2.2 (CD8) monoclonal antibody (mAb) on days zero, four and 14 into recipient mice prolonged their survival for at least the 200-day observation period. Injection of anti-L3T4 (CD4) mAb also prolonged survival of the mice for more than 70 days, but they eventually died by 150 days. Pretreatment of the donor B6 spleen cells with anti-Lyt-2.2 (CD8) mAb and complement (C) prevented the development of GVHD, and their pretreatment with anti-L3T4 (CD4) mAb and C markedly prolonged the survival of recipient mice. Injection of a mixture of donor spleen cells pretreated with anti-Lyt-2.2 (CD8) mAb and C and those pretreated with anti-L3T4 (CD4) mAb and C induced subacute lethal GVHD. Injection of anti-L3T4 (CD4) mAb, but not anti-Lyt-2.2 (CD8) mAb on days five, nine and 14 prolonged survival of the recipient mice. These results indicated that the collaboration of CD8+ cells and CD4+ cells was necessary for induction of subacute lethal GVHD. CD4+ cells but not CD8+ cells were involved in mediating subacute GVHD from the onset of the disease. CD8+ cells were, however, capable of inducing late-onset lethal GVHD. Direct phenotyping of T cells in the recipient mice revealed that the CD4+ cells were incapable of repopulating without CD8+ cells, but that CD8+ cells were capable of repopulating without CD4+ cells.

Rejection of an IA+ variant line of FBL-3 leukemia by cytotoxic T lymphocytes with CD4+ and CD4-CD8- T cell receptor-alpha beta phenotypes generated in CD8-depleted C57BL/6 mice

FBL-3N is an MHC class II Ag+ variant line that was obtained spontaneously during maintenance of Friend virus-induced leukemia FBL-3 in an athymic C57BL/6 (B6) mouse. Inocula of FBL-3N, but not the parental FBL-3 tumor, regressed after initial growth in CD8-depleted, syngeneic B6 mice. The cellular mechanisms by which FBL-3N was rejected in these mice were investigated in this study. We demonstrated that CTL with both CD4+ and CD4-CD8-TCR-alpha beta phenotypes were generated in mixed lymphocyte tumor cell culture spleen cells obtained from CD8-depleted B6 mice that had rejected FBL-3N by in vitro stimulation with mitomycin C-treated FBL-3N. After adoptive transfer of these CTL that were generated in vitro into athymic B6 mice, challenge with the FBL-3N tumor resulted in tumor regression after its initial growth. Thus, CD4+ and CD4-CD8-TCR-alpha beta CTL mediated rejection of the FBL-3N tumor in CD8-depleted B6 mice. Furthermore, the findings that depletion of B6 mice of CD4+ cells in addition to CD8+ cells abrogated the rejection of FBL-3N and generation of CTL in mixed lymphocyte tumor cell culture spleen cells suggest that CD4+ cells were required not only as a source of CD4+ CTL, but also as helper cells for generation of CD4-CD8-TCR-alpha beta CTL. Tumor Ag recognition of CD4-CD8-TCR-alpha beta CTL was restricted to Db, like that of classical CD8+ CTL, but the restriction appeared to be less obligatory than that of CD8+ CTL.

Rejection of an IA+ variant line of FBL-3 leukemia by cytotoxic T lymphocytes with CD4+ and CD4-CD8- T cell receptor-alpha beta phenotypes generated in CD8-depleted C57BL/6 mice

FBL-3N is an MHC class II Ag+ variant line that was obtained spontaneously during maintenance of Friend virus-induced leukemia FBL-3 in an athymic C57BL/6 (B6) mouse. Inocula of FBL-3N, but not the parental FBL-3 tumor, regressed after initial growth in CD8-depleted, syngeneic B6 mice. The cellular mechanisms by which FBL-3N was rejected in these mice were investigated in this study. We demonstrated that CTL with both CD4+ and CD4-CD8-TCR-alpha beta phenotypes were generated in mixed lymphocyte tumor cell culture spleen cells obtained from CD8-depleted B6 mice that had rejected FBL-3N by in vitro stimulation with mitomycin C-treated FBL-3N. After adoptive transfer of these CTL that were generated in vitro into athymic B6 mice, challenge with the FBL-3N tumor resulted in tumor regression after its initial growth. Thus, CD4+ and CD4-CD8-TCR-alpha beta CTL mediated rejection of the FBL-3N tumor in CD8-depleted B6 mice. Furthermore, the findings that depletion of B6 mice of CD4+ cells in addition to CD8+ cells abrogated the rejection of FBL-3N and generation of CTL in mixed lymphocyte tumor cell culture spleen cells suggest that CD4+ cells were required not only as a source of CD4+ CTL, but also as helper cells for generation of CD4-CD8-TCR-alpha beta CTL. Tumor Ag recognition of CD4-CD8-TCR-alpha beta CTL was restricted to Db, like that of classical CD8+ CTL, but the restriction appeared to be less obligatory than that of CD8+ CTL.

Relationship between the anti-HTLV-1 antibody level, the number of abnormal lymphocytes and the viral-genome dose in HTLV-1-infected individuals

Two distinct diseases, adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), develop in a minor population of HTLV-1 carriers. We examined the relationship between the viral genome dose in the peripheral-blood mononuclear cells and the serological response in HTLV-1 carriers and patients with HAM/TSP. The antibody titer to HTLV-1 gag and env proteins, as well as the frequency of an antibody response to viral protein p40tax and the titer, increased with increasing viral genome dose. However, the number of abnormal lymphocytes was not directly related to the host viral load. Patients with HAM/TSP generally showed a higher genome dose than healthy carriers and also had higher antibody titers than healthy carriers with the same HTLV-1 load, supporting the existence of an augmented immune response in these patients. These findings suggest that the antibody titer to HTLV-1 genome products, and not the number of abnormal lymphocytes, intimately reflects the approximate viral load in HTLV-1-infected individuals.

Effect of accessory cells on stimulation of murine T-cell leukemia with antibodies to the CD3/T cell antigen receptor complex

Stimulation of EL4 and RL male 1 leukemia cells in vitro with immobilized anti-CD3 epsilon monoclonal antibody (mAb) (145-2C11) or anti-TCR beta mAb (H57-597) in the absence of accessory cells induced interleukin-2 (IL-2) production, and caused growth inhibition. The growth inhibition was, however, transient and the tumors started to grow again within 5 days in immobilizing plates treated with antibodies at concentrations of 2.5-100 micrograms/ml. Addition of mitomycin C-treated accessory cells to the culture inhibited IL-2 production and resulted in augmented and persistent growth inhibition. No recovery of tumor growth was observed. Furthermore, DNA from EL4 and RL male 1 leukemia cells stimulated with anti-CD3/TCR mAbs was fragmented even in the absence of accessory cells, but fragmentation was much greater in the presence of accessory cells. Marginal and high expression of the bcl-2 gene were observed in EL4 and RL male 1, respectively, indicating that apoptosis of these leukemias mediated by signalling through the CD3/TCR complex has no direct relationship with expression of the bcl-2 gene.

Clinical symptoms of open lock position of the condyle. Relation to anterior dislocation of the temporomandibular joint

Nine cases of open lock position of the condyle of the temporomandibular joint (TMJ) are reported. In two patients recurrent dislocation of the TMJ was diagnosed clinically, and four had previous episodes of anterior dislocation. An arthrotomographic examination revealed that the condyles of the affected TMJs were located anterior to the anterior bands of the disks at an open-mouth position. An arthrographic fluoroscopic examination showed that the anterior bands mechanically obstructed the anteriorly displaced condyles from posterior movement into the articular fossae to various degrees at open-mouth position. One cause of anterior dislocation of the TMJ is thought to be fixation of the condyle in the open lock position resulting from a disturbance of a neuromuscular mechanism. In the two patients with dislocation, occlusal treatment eliminated muscular symptoms and the dislocations completely disappeared.

Kinase group protooncogenes in non-hodgkins-lymphomas and nonmalignant lymphoid-tissues - analysis of their expression by insitu hybridization assays

Expression of src related proto-oncogenes in non-Hodgkin's lymphomas and non-malignant lymph nodes was analyzed by means of in situ hybridization assays with biotinylated DNA probes. In 36 cases of non-Hodgkin's lymphomas, both c-mos and c-abl were expressed in 27 cases, and c-erbB and c-src were expressed in 15 cases and 7 cases, respectively. No case expressed c-fps or c-yes. On the contrary, in 11 cases of non-malignant lymph nodes c-erbB and c-mos was expressed in only 3 cases. No other proto-oncogenes were expressed. Lymphomas in general express multiple proto-oncogenes simultaneously. A variety of combinations of expressed proto-oncogenes were observed suggesting diversity among non-Hodgkin's lymphomas in biological characteristics. However, a clear association with the expression of a single proto-oncogene or the number of expressed proto-oncogenes with T cell / B cell types, or the histopathological classification of NHL, or disease prognosis was not observed.

Inhibition of B6RV2 leukemia growth by immunization with purified unique antigen

Monoclonal antibody (mAb) NU7-99 reacted with only B6RV2 cells, not with 28 other leukemia cell lines, fibroblasts or normal tissues. Biochemical analyses of the unique antigen on B6RV2 cells that reacted with NU7-99 mAb indicated its relationship to xenotropic murine leukemia virus gp70. The antigen that reacted with NU7-99 mAb was extracted from the surface of B6RV2 cells with n-butanol and purified by ion-exchange chromatography and affinity chromatography. Growth of B6RV2 tumors in semi-syngeneic mice was inhibited by immunization of the mice with a purified preparation of this unique antigen.

Semiquantitative analysis of integrated genomes of human T-lymphotropic virus type I in asymptomatic virus carriers

A semiquantitative estimation of human T-lymphotropic virus type I (HTLV-I) integration by peripheral blood mononuclear cells (PBMC) was performed. Genomic DNA samples derived from 134 HTLV-I carriers were subjected to 40 or 60 cycles of the polymerase chain reaction to amplify the pol region of HTLV-I. The HTLV-I genome was detected by dot hybridization using a 32P-labeled oligonucleotide probe for the pol region. The radioactivity of hybridized dot membranes was then counted with an RI Imaging System (Ambis Inc, San Diego, CA) and the HTLV-I genome dose was determined by comparison with standard curve for serially diluted HTLV-I genome-positive DNA. A wide range of variation of HTLV-I genome integration was observed. When the integrated genome dose was calculated as the number of HTLV-I copies per 100 PBMC, 7 carriers (5%) had more than 10 copies, 56 (42%) had 1 to 10 copies, 46 (34%) had 0.1 to 1 copy, and 24 (18%) had less than 0.1 copy. In one sample, the HTLV-I genome was undetectable, which may indicate that the integrated genome was present at less than 0.01 copies per 100 PBMC. Age- or sex-related variations in the distribution of individuals with different HTLV-I genome were rather limited. However, carriers with a high level of the HTLV-I genome were always more than 30 years old and were predominantly male (six of seven).

Cephalosporin antibiotics. I. Synthesis and structure-activity relationships of 3-thiazoliomethyl derivatives

The synthesis and the structure-activity relationships of 3-thiazoliomethyl cephalosporins are described. In a series of these parenteral compounds, 2-(2-aminothiazol-4-yl)-(Z)-2-methoxy-iminoacetamido group was found to be a favorable substituent for the C-7 position of the cephem nucleus. They showed potent antibacterial activity against both Gram-positive and Gram-negative bacteria including some beta-lactamase producing species.

Cephalosporin antibiotics. II. Synthesis and biological properties of CS-461 and related compounds

The synthesis, structure-activity relationships, and biological properties of 3-thiazoliomethyl cephalosporins are described. 7-[2-(2-Aminothiazol-4-yl)-(Z)-2- methoxyiminoacetamido]-3-[5-(2-hydroxyethyl)-4-methylthiazoliomethyl+ ++]-3- cephem-4-carboxylate sulfate (CS-461) showed potent antibacterial activity against a wide variety of bacteria both in vitro and in vivo. Furthermore, CS-461 exhibited significantly low acute toxicity in mice.

CD4-CD8- T cell receptor alpha beta T cells: generation of an in vitro major histocompatibility complex class I specific cytotoxic T lymphocyte response and allogeneic tumor rejection

The generation of an in vitro major histocompatibility complex class I specific response of CD4-CD8- T cell receptor (TCR) alpha beta cytotoxic T lymphocytes (CTL) and their allogeneic tumor rejection were investigated. Inocula of BALBRL male 1 were rejected in C57BL/6 (B6) mice treated with minimum essential medium (MEM) (control), anti-L3T4 (CD4) monoclonal antibody (mAb) or anti-Lyt-2.2 (CD8) mAb and CTL against the tumor were generated in vitro. No rejection and no induction of CTL were observed in B6 mice treated with anti-L3T4 (CD4) plus anti-Lyt-2.2 (CD8) mAb. CTL with the classical Thy-1+ CD3+CD4-CD8+ TCR alpha beta phenotype were generated in mixed lymphocyte tumor cell culture (MLTC) spleen cells from B6 mice treated with MEM (control) or anti-L3T4 (CD4) mAb, whereas CTL with an unusual Thy-1+CD3+CD4-CD8- TCR alpha beta phenotype were generated in MLTC spleen cells from anti-Lyt-2.2 (CD8) mAb-treated B6 mice. Both types of CTL were reactive with both H-2Kd and Dd (Ld) class I antigen. These findings suggest that when CD4+ cells were blocked by anti-L3T4 (CD4) mAb, CD8+ CTL mediated rejection, and when CD8+ cells were blocked by anti-Lyt-2.2 (CD8) mAb, CD4+ cells were capable of mediating rejection, although less efficiently than CD8+ cells, by inducing CD4-CD8- TCR alpha beta CTL. The finding that adoptive transfer of CD4 and CD8-depleted MLTC spleen cells, obtained from anti-Lyt-2.2 (CD8) mAb-treated B6 mice that had rejected BALBRL male 1, resulted in rejection of BALBRL male 1 inoculated into B6 nu/nu mice confirmed the above notion. CTL clones with the CD4-CD8- TCR alpha beta phenotype specific for Ld were established.

Induction of in vitro and in vivo anti-tumor responses by sensitization of mice with liposomes containing a crude butanol extract of leukemia cells and transferred inter-membranously with cell-surface proteins

Generation of cytotoxic T lymphocytes (CTL) in vitro and tumor-rejection responses by sensitization of semi-syngeneic mice with tumor-antigen-reconstituted liposomes were investigated. Liposomes were prepared from a crude butanol extract (CBE) of BALBRVD leukemia cells and egg phosphatidylcholine (PC): 1,2-dimyristoylamido-1,2-deoxyphosphatidylcholine (DDPC) (3:2) or dimyristoylphosphatidylcholine (DMPC):DDPC (1:4). Inter-membrane protein transfer (IMPT) liposomes were prepared by incubating BALBRVD cells with DMPC:DDPC (1:4) liposomes. Sensitization of male CB6F1 mice with CBE or IMPT liposomes induced a level of cytotoxicity similar to that on sensitization with mitomycin-C(MMC)-treated BALBRVD against BALBRVD target cells after in vitro sensitization with the tumor cells. Sensitization with CBE alone resulted in only marginal cytotoxicity. The cytotoxic effector cells induced by either mode of sensitization were CD8+ T-cells whose recognition was Kd-restricted. No difference in specificity was observed with the different modes of sensitization. Two in vivo immunizations with CBE or with CBE liposomes at a dose of 25 micrograms of protein (equivalent to 2.5 x 10(7) cells) cause moderate inhibition of BALBRVD tumor growth in male CB6F1 mice and immunization with IMPT liposomes at a dose of 1 microgram of protein result in efficient protection.

Priming for in vitro and in vivo anti-human T lymphotropic virus type 1 cellular immunity by virus-related protein reconstituted into liposome

In vitro and in vivo anti-human T lymphotropic virus type 1 (HTLV-1) cellular immunity was examined by immunizing rats with a truncated hybrid protein (228 amino acids) of gag and env of HTLV-1 produced by Escherichia coli. Animals were immunized with the hybrid protein reconstituted into mannan-derivative-coated liposomes (gag-env-lipo). In vitro sensitization with a HTLV-1-positive cell line, TARS-1, of spleen cells obtained from these animals generated killer cells specific for syngeneic HTLV-1-positive cells. No killer activity was generated when spleen cells were obtained from animals immunized with the hybrid protein alone, the liposome alone, or the hybrid protein reconstituted into conventional liposomes with no polysaccharide coating. Killer cells were CD8+ CTL restricted to MHC class I. Analysis of CD8+ and CD4+ subsets in spleens showed the existence of primed CD8+ T cells in animals immunized with gag-env-lipo. Rats immunized with gag-env-lipo displayed accelerated rejection of TARS-1 but not of two other HTLV-1-negative tumor lines. Injection of carrageenan into animals strongly inhibited generation of killer cells, which indicates the necessity of macrophages for priming of CD8+ T cells with gag-env-lipo. Injection of carrageenan also cancelled in vivo immunity against HTLV-1+ cells induced with gag-env-lipo. These results, taken together, indicate that exogenous protein reconstituted into appropriate liposomes can effectively prime MHC class I restricted CD8+ T cells in vivo with macrophage dependency.

Priming for in vitro and in vivo anti-human T lymphotropic virus type 1 cellular immunity by virus-related protein reconstituted into liposome

In vitro and in vivo anti-human T lymphotropic virus type 1 (HTLV-1) cellular immunity was examined by immunizing rats with a truncated hybrid protein (228 amino acids) of gag and env of HTLV-1 produced by Escherichia coli. Animals were immunized with the hybrid protein reconstituted into mannan-derivative-coated liposomes (gag-env-lipo). In vitro sensitization with a HTLV-1-positive cell line, TARS-1, of spleen cells obtained from these animals generated killer cells specific for syngeneic HTLV-1-positive cells. No killer activity was generated when spleen cells were obtained from animals immunized with the hybrid protein alone, the liposome alone, or the hybrid protein reconstituted into conventional liposomes with no polysaccharide coating. Killer cells were CD8+ CTL restricted to MHC class I. Analysis of CD8+ and CD4+ subsets in spleens showed the existence of primed CD8+ T cells in animals immunized with gag-env-lipo. Rats immunized with gag-env-lipo displayed accelerated rejection of TARS-1 but not of two other HTLV-1-negative tumor lines. Injection of carrageenan into animals strongly inhibited generation of killer cells, which indicates the necessity of macrophages for priming of CD8+ T cells with gag-env-lipo. Injection of carrageenan also cancelled in vivo immunity against HTLV-1+ cells induced with gag-env-lipo. These results, taken together, indicate that exogenous protein reconstituted into appropriate liposomes can effectively prime MHC class I restricted CD8+ T cells in vivo with macrophage dependency.

Similarity of expression of low molecular weight G proteins smg p21A and ras p21 in normal and malignant human tissues

We prepared monoclonal antibodies specific for smg p21A, one of the low molecular weight GTP-binding proteins and possibly a suppressor molecule for ras p21. Two monoclonal antibodies (T22 and T212) reacted with smg p21A but not with Ki-ras p21, both of which were produced by Escherichia coli. These two clones detected an Mr 21,000 band in one-dimensional immunoblotting of extracts of a human pancreatic cancer cell line which was indistinguishable from a band detected by RASK-3, a monoclonal antibody specific for ras p21. However, T22 and T212 detected a single spot in two-dimensional immunoblotting that was clearly different from the three spots detected in the same cellular extracts by RASK-3. A series of normal and malignant human tissues were examined for the expression of smg p21A and ras p21 by immunohistochemical methods utilizing T22 and RASK-3. In essentially all tissues examined, both normal and malignant, smg p21A and ras p21 were expressed with great similarity. Expression of both molecules in all malignant tissues examined was coincident with that in normal tissues except that gastric cancer showed increased expression of the two molecules in comparison with normal gastric tissue.

Differential involvement of CD4+ cells in mediating skin graft rejection against different amounts of transgenic H-2K(b) antigen

Differential involvement of CD4+ cells in mediating class I-disparate skin graft rejection was investigated using quantitatively different Kb transgenic mice as donors under conditions in which CD8+ cells were blocked in vivo by administration of anti-CD8 monoclonal antibody (mAb). Tg.H-2Kb-1 and -2 are C3H transgenic mice with 14 and 4 copies, respectively, of the H-2Kb gene. Cell surface expression of Kb antigen and the Kb antigenicity of skin for eliciting graft rejection with homozygous and heterozygous transgenic mice were correlated with the copy number. In vivo administration of anti-Lyt-2.1 (CD8) mAb markedly prolonged survival of heterozygous and homozygous C3H Tg.H-2Kb-2 skin grafted onto C3H mice, but prolonged survival of heterozygous Tg.H-2Kb-1 skin grafts much less and did not prolong survival of homozygous Tg.H-2Kb-1 grafts. Administration of anti-L3T4 (CD4) mAb alone did not have any effect on skin graft rejection. Administration of anti-L3T4 (CD4) mAb with anti-Lyt-2.1 (CD8) mAb blocked rejection in all combinations. These findings indicate that a quantitative difference of class I antigen caused differential activation of CD4+ cells under conditions in which CD8+ cells were blocked.

Detection of the c-myc gene product in urinary bladder cancer

Expression of the c-myc gene product in urinary bladder cancer was investigated by immunohistochemical staining with anti-c-myc monoclonal antibody (mAb) MYC-1. Positive staining was observed in the cytoplasm, but not in the nucleus in tissues fixed with 10% formalin. On the other hand, positive staining was localized in the nucleus in cryopreserved tissues. Of 34 cryopreserved specimens examined, positive staining with MYC-1 mAb was observed in 1 of 12 (8.3%) of grade 1 (G1), 12 of 15 (80%) of G2 and 6 of 7 (86%) of G3. Positive staining with Ki-67 mAb was observed in 2 of 12 (17%) of G1, 12 of 15 (80%) of G2, and 6 of 7 (86%) of G3. These results suggest that tumors with higher nuclear pleomorphism contain more proliferating cells.