Heart in hypothyroidism--an echocardiographic study

55 individuals, 44 of whom served as patients and 11 as controls were included in this study. Patient group was further divided into overt and subclinical hypothyroid group each having 22 patients. Patients were examined in a prospective manner and results compared with control group with an aim to evaluate the effect of hypothyroidism subclinical and overt on cardiac status by echocardiography. Variables of heart structure and function were assessed by cross sectional and Doppler echocardiography. IVS dimensions were significantly raised in moderate subclinical and in severe overt hypothyroidism (mean 0.911 +/- 0.038 and 0.973 +/- 0.217 cm). LVPW thickness was significantly increased only in overt hypothyroidism (mean 1.378 +/- 0.246). However RVW and LVID showed no definite pattern of change. Pericardial effusion and Diastolic dysfunction was seen in significant cases only in overt hypothyroidism. To conclude, hypothyroidism both subclinical and overt is associated with cardiovascular alteration both structural and functional. IVS and LVPW thickness are markedly affected, as well as there is impairment of left ventricular function more in diastole.

Inhibition of Epstein-Barr-virus-transformed human chronic lymphocytic leukaemic B cells with monoclonal-antibody-adriamycin (doxorubicin) conjugates

The anthracyclin antineoplastic agent doxorubicin (Adriamycin) was linked by four different methods of linkage to DalB02, an IgG1 kappa murine monoclonal antibody (mAb) against surface-associated antigens on human chronic lymphocytic leukaemia (CLL) B cells. All the four conjugates fully retained the immunoreactivity of the parent DalB02. When the inhibitory effect of these conjugates was evaluated in vitro against the target D10-1 cells (a clone derived from an Epstein-Barr-virus-transformed human CLL B cell line that binds DalB02) it was observed that one conjugate was more potent than the free drug but the others were not. When 131I-labelled unmodified DalB02 and the 131I-labelled DalB02-containing conjugate that was found to be potent were injected i.v. into nude mice bearing a subcutaneous D10-1 xenograft, the percentages of the injected dose (%ID) of both 131I-DalB02 and the 131I-DalB02-containing conjugate that localized in the tumour were much higher than the %ID of the respective preparations that localized in normal tissues of D10-1-xenografted mice. The systemic toxicity of the conjugate was less than that of the free drug. At an equitoxic dose level, this conjugate was a more effective inhibitor of established D10-1 xenografts than the free drug.

Monoclonal-antibodies to human breast-cancer associated antigens

Eleven murine monoclonal antibodies (MABs) were produced using human mammary cancer (HMC) cell lines as immunogens: None reacted with normal breast tissue, but each had a distinctive pattern of reactivity with HMC and benign proliferative lesions. Two MABs bound to overlapping epitopes of an M(r) 47,000 cell-surface antigen and were endocytosed: nine bound to secretable intracytoplasmic antigens(s). Four of the MABs immunoprecipitate antigens that upon reduction yielded an M(r) 73,000 moiety. None reacted with components of milk. All antigens were sensitive to trypsin, three to periodate oxidation but none to neuraminidase. One cell-surface-localizing MAB investigated, selectively localized in HMC xenografts.

Synthesis and characterization of carbohydrate-linked murine monoclonal antibody K20-human serum albumin conjugates

Efficacy of antibody mediated targeting depends on retention of immunoreactivity in conjugates. Retention can be improved by site-specific linkage of drugs or drug-loaded carriers to residues that are located well away from the antigen-binding sites. In this study we describe the site-specific linkage of a potential drug carrier, human serum albumin (HSA), to the carbohydrate residues in Dal K20, a murine IgG1 monoclonal antibody (mAb) against human renal cell carcinoma, using disulfide exchange between 3-(2-pyridyldithio)propionic acid succinimidyl ester (SPDP)-derivatized HSA and 11-[[3-(2-pyridyldithio)propionyl]amino]undecanoic acid hydrazide (AUPDP)-derivatized mAb Dal K20. AUPDP gave a higher yield of the conjugate than a functionally analogous 3-(2-pyridyldithio)propionic acid hydrazide (HPDP), suggesting that the extra length of the former facilitated the linkage. The conjugates were found to be unstable without reduction of the hydrazone linkage using sodium cyanoborohydride. Stabilized 1:1 HSA:K20 carbohydrate-linked conjugates were isolated and compared with non-site-specific 1:1 conjugates in which HSA was conjugated to amino groups in mAb Dal K20. The yield and stability of the two conjugates were comparable, but the site-specific conjugate was found to retain three times more antibody activity than the non-site-specific conjugate.

Tumor localization and therapeutic potential of an antitumor-anti-CD3 heteroconjugate antibody in human renal cell carcinoma xenograft models

A heteroconjugate (HC) antibody, constructed with the monoclonal antibody (MoAB) Dal K29 to human renal cell carcinoma (RCC) and an anti-CD3 MoAb, could induce a very high level of lysis of human RCC cells when incubated with human peripheral blood lymphocytes (PBL) in vitro (Kerr et al., 1990, J. Immunol., 144, 4060-4067). We now report that this HC antibody selectively localizes in RCC xenografts in nude mice and could inhibit RCC in an ascites tumor xenograft model when administered intraperitoneally together with PBL.

Radioimmunotherapy of human B-cell chronic lymphocytic leukemia in nude mice

After i.v. or i.p. inoculation of 5 x 10(6) D10-1 cells, a subclone of an Epstein-Barr virus transformed human B-cell chronic lymphocytic leukemia (CLL) line, 100% of nude mice developed solid or ascites tumors and died within 17-60 days of tumor inoculation. There was significant tumor inhibition, including tumor cure, when these tumor-inoculated mice were treated with either unmodified or 131I (300 microCi)-linked Dal B02 (50 micrograms/mouse), a monoclonal antibody directed against surface-associated antigens on human CLL B-cells and several histological types of B-lymphoma cells. There was no significant difference between the antitumor activity of unmodified Dal B02 and 131I-linked Dal B02 when the treatment was given 3 days after i.p. or i.v. inoculation of 5 x 10(6) D10-1 cells. However, when the mice were treated 3 days after i.p. inoculation of 15 x 10(6) D10-1 cells, or 7 days after the i.v. inoculation of 5 x 10(6) D10-1 cells, 131I-linked Dal B02 was a more potent tumor inhibitor than was unmodified Dal B02 (P < 0.05 and P < 0.01, respectively). Two injections of 131I (500 microCi) linked to 100 micrograms of a Dal B02 F(ab')2 fragment preparation also prolonged the survival of i.p. or i.v. tumor-inoculated mice (P < 0.05 and P = 0.05, respectively). In nude mice with established s.c. xenografts of D10-1 cells, two injections of 131I (300 microCi) linked to 50 micrograms of Dal B02 led to complete tumor cure in 3 of 4, mice, but two injections of 50 micrograms of unmodified Dal B02 had no effect on the s.c. xenografts. Two injections of 131I (500 microCI) linked to 100 micrograms of Dal B02 F(ab')2 fragment caused significant tumor inhibition but no tumor cure. 131I (300 microCi) linked to 50 micrograms of a nonspecific IgG1 only led to minor tumor inhibition. A mixture of unmodified Dal B02 and 131I-linked nonspecific IgG1 was not a more potent tumor inhibitor than the 131I-linked nonspecific IgG1 preparation by itself. These results suggest that Dal B02 may be an effective carrier for the radioimmunotherapy of human B-cell CLL and other appropriate B-cell lymphomas, especially in the progressive phase of B-cell CLL, which is usually not amenable to currently available therapeutic modalities.

Immunoreactivity, stability, pharmacokinetics and biodistribution of a monoclonal antibody to human leukemic B cells after three different methods of radioiodination

Dal B02, a murine monoclonal antibody against human chronic lymphocytic leukemia (CLL) was radioiodinated using chloramine T (Chl.T), Bolton-Hunter (B-H) or N-succinimidyl-p-iodobenzoate (PIB). The preparations had comparable radiochemical purity (> 97%) and immunoreactive fraction (65-80%) but the Chl.T-based product was most susceptible to deiodination and loss of immunoreactivity. After i.v. injection into CLL-xenografted nude mice, the preparations had identical patterns of clearance from the blood but the PIB-based product led to more radioactivity in liver and spleen and less in the thyroid compared to the other preparations. The Chl.T-based product showed loss of immunoreactivity in circulation and less tumor-localized radioactivity 168 h after administration. The differences between the B-H-based and PIB-based products were less impressive than between PIB-based and Chl.T-based products.

Inhibition of human B-cell chronic lymphocytic leukemia by a monoclonal antibody in xenograft models

To establish xenograft models of human B-cell chronic lymphocytic leukemia (CLL), we inoculated 5 x 10(6) D10-1 cells, a subline of Epstein-Barr virus (EBV)-transformed human B-cell CLL with a marker chromosomal anomaly, into SCID or irradiated nude mice by the intravenous (i.v.) or intraperitoneal (i.p.) route. All i.p. tumor-inoculated mice developed rapidly progressive, lethal ascites tumor, and 100% of i.v. tumor-inoculated mice developed disseminated CLL. All mice died of tumor within 8 weeks of tumor inoculation. Tumor-inoculated SCID mice died earlier with wider tumor dissemination than the tumor-inoculated nude mice. All the tumor-inoculated mice had histologically confirmed metastases in lymph nodes, and most of them also had metastases in one or more internal organs. Cytogenetic analysis confirmed the origin of these tumors from the xenografted D10-1 cells. The D10-1 cells harvested from the xenografts did not differ from the parent D10-1 cells as regards (i) reactivity with 2 monoclonal antibodies (MAbs) directed against CLL-associated cell-surface antigens; (ii) rate of proliferation in vitro; and (iii) sensitivity to the 2 chemotherapeutic agents, methotrexate and adriamycin. Administration of 50 micrograms/mouse of Dal B02, an IgG1 (kappa) MAb directed against surface-associated antigens of human B-cell CLL, significantly prolonged the survival of D10-1-inoculated nude and SCID mice. The MAb was more effective in D10-1-inoculated nude mice than in SCID mice. In all the D10-1 xenograft models, the effectiveness of Dal B02 decreased with higher tumor load but increased with the amount of MAb injected. Dal B02 F(ab)'2 fragment failed to demonstrate any anti-tumor activity in D10-1-inoculated nude mice. In vitro assays revealed that Dal B02 had no direct inhibitory effect on D10-1 cells, but could be cytotoxic towards D10-1 cells in the presence of splenic cells or peritoneal macrophages from nude and SCID mice, or together with rabbit complement.

Pharmacokinetics, biodistribution and tumor localization of two anti-human B-cell chronic lymphocytic leukemia monoclonal antibodies and their F(ab)'2 fragments in a xenograft model

We investigated the pharmacokinetics, biodistribution and tumor localization of intravenously injected Dal B01 and Dal B02, two monoclonal antibodies (MoAbs) directed against tumor associated antigens on human chronic lymphocytic leukemia (CLL) B cells, and their F(ab)'2 fragments in nude mice bearing xenografts of the human B cell CLL line D10-1. More of the percentages of the injected dose (% ID) of these two MoAbs and their F(ab)'2 fragments specifically localized in the tumor xenografts than in normal tissues. Compared to intact MoAbs, their F(ab)'2 fragments had lower % ID in tumors and were cleared from circulation faster. Well-defined tumor images were obtained at 24 and 48 h after administration of [131I]Dal B02 F(ab)'2 fragment and at 96-192 h after administration of [131I]Dal B02. A comparison between intravenous and intraperitoneal routes of administration of [131I]Dal B02 did not reveal any difference in the localization of % ID in tumor or normal tissues.

Alpha 1-antitrypsin as a biomarker in azoxymethane induced intestinal tumors in F344 rats

Alpha 1-antitrypsin (alpha 1AT) has been detected in several human tumors and is thought to be a marker of neoplastic change and progression. As the biology of azoxymethane (AOM) induced intestinal tumors in F344 rats has many characteristics of human intestinal tumors, we have investigated alpha 1AT expression in AOM induced rat intestinal tumors. Nine of 12 colonic carcinomas and 6/8 small intestinal carcinomas had alpha 1AT positive tumor cells. Only 1/11 colonic adenomas and 0/3 small intestinal adenomas contained alpha 1AT. Thus alpha 1AT is a marker of malignancy in this model. Inhibition of carcinogenesis by piroxicam and difluoromethyl ornithine inhibited alpha 1AT expression.

Keratin and carcinoembryonic antigen (CEA) in human melanoma cells

Human melanomas are known to contain vimentin intermediate filaments but there has been some dispute about their expression of cytokeratins. The cytoplasm of human M21 melanoma cells maintained in culture reacted with a rabbit anti-keratin antibody and two monoclonal anti-keratin antibodies AE1 and AE2. Cells derived directly from subcutaneous xenografts of M21 melanoma in nude mice, however, failed to express cytokeratins. The presence of keratin filaments in cultured M21 cells was confirmed by electronmicroscopic and immuno-electronmicroscopic examinations of cell extracts. Polyacrylamide gel electrophoresis (PAGE), revealed 46 KD keratin proteins in cultured M21 cells. Small amounts of these low molecular weight keratins were detected by PAGE in M21 melanoma xenografts even though immunofluorescence and immunoperoxidase assays failed to demonstrate keratin at the light microscopic level. Immunofluorescence revealed keratin and carcinoembryonic antigen (hitherto undetected in human melanomas) first on the 9th day of culture of xenograft-derived M21 cells. The appearance of keratin and CEA in M21 melanoma cells in vitro was not affected by inhibition of cellular proliferation or as a result of exposure to methotrexate or adriamycin. However, adriamycin altered the cytoplasmic distribution of keratin.

Ipsilateral fractures of the distal radius and scaphoid treated by Herbert screw and external skeletal fixation. A report of two cases

Two patients with comminuted, displaced fractures of the distal radius associated with ipsilateral, undisplaced scaphoid fractures were treated by internal fixation of the scaphoid fracture with a Herbert screw in association with external fixation of the distal radial fracture. One of the patients had a limited open reduction of the distal radius combined with bone grafting. Both patients had satisfactory results. Internal fixation of the scaphoid is indicated if distraction is applied to the carpus to treat an associated fracture of the distal radius, even if the scaphoid fracture is undisplaced.

Tumor localization of monoclonal antibodies against human renal carcinoma in a xenograft model

We investigated the localization of intravenously injected DAL K45 and DAL K29, two monoclonal antibodies (MABs) against human renal cell carcinoma (RCC), and their F(ab)2 fragments in nude mice bearing intrarenal transplants of the RCC line Caki-1. More of the MABs or their F(ab)2s specifically localized in the tumor than in any normal tissue with the exception of blood. Compared to parent MABs, F(ab)2s were cleared faster from all tissues. In serum, the MABs and F(ab)2s showed a single radioactive peak retaining partial immunoreactivity. DAL K45-F(ab)2 showed the highest tumor:normal tissue localization ratios and the most distinct gamma-camera image at 24 h.

Retardation in tumor growth and metastasis demonstrated in a human CLL B-cell line after the acquisition of an extra chromosome 11

In this study we described the isolation of a subclonal EBV-transformed human CLL B-cell line with retarded growth rate and metastatic potential from its clonal parent (D10-1), which was karyotyped: 46.XY.dup(1)(q11----q32). The subclone, designated D10-1C, was isolated by limiting dilution of D10-1 following selection in 8-azaguanine-supplemented medium. Chromosome analysis of D10-1C revealed a constitution of 47,XY, + 11.dup(1)(q11----q32). This is the first demonstration that partial trisomy 1q-associated growth advantage in human cancer cells can be retarded by the presence of an additional dose of chromosome 11. Human chromosome 11 had been shown to be responsible for the suppression of tumor development. Whether the same suppressor genes are involved in D10-1C remains to be elucidated. The procedure described here for the enrichment and isolation of a growth-retarded mutant from D10-1 may be applicable in other malignant cell systems.

Inhibition of human renal cancer by monoclonal antibody targeted methotrexate-containing liposomes in an ascites tumor model

The monoclonal antibody DAL K29 against a human renal cell carcinoma associated cell surface antigen was covalently linked to small unilamellar lipid vesicles (SUV) containing the antifolate, methotrexate (MTX), with full retention of antibody activity. In an ascites tumor model developed after intraperitoneal inoculation of 5 x 10(6) cells of the human kidney cancer line Caki-1 per pristane primed nude mouse, the DAL K29 linked MTX-containing SUV was a more potent tumor inhibitor (P less than 0.0005) than the drug or MAB alone, MTX-containing SUV, a mixture of DAL K29 and MTX-containing SUV or MTX-containing SUV linked to an isotype matched nontumor specific IgG.

Regression of human melanoma xenografts in nude mice injected with methotrexate linked to monoclonal antibody 225.28 to human high molecular weight-melanoma associated antigen

Intravenous injections into nude mice of 5 mg/kg methotrexate (MTX) linked to the antibody to human high molecular weight-melanoma associated antigen (HMW-MAA), monoclonal antibody (mAb) 225.28, an IgG2a, on days 1, 4, 7, 10 and 14, starting 24 h after subcutaneous inoculation of 2 x 10(6) cultured human M21 melanoma cells inhibited mean tumor volume by 90% on day 14 and by 65% on day 50 after the beginning of the treatment. Injections of equimolar amounts of free MTX and MTX linked to normal mouse IgG or to an isotype-matched myeloma protein did not inhibit tumor growth significantly. MTX linked to mAb 225.28 did not inhibit the xenograft of a subline of human melanoma cell line M21 without detectable expression of HMW-MAA. In a clonogenic assay, the MTX-225.28 conjugate was three times more potent in inhibiting the growth of M21 melanoma cells than free MTX, but did not inhibit the growth of kidney carcinoma cells Caki-1, which do not express high-Mr MAA. In contrast, MTX linked to the mAb DAL K29, reacting with kidney carcinoma cells Caki-1, inhibited their growth but did not affect that of melanoma cells. M21 melanoma cells isolated from the residual tumor of a mouse treated with the MTX-225.28 conjugate did not differ in their reactivity with mAb 225.28 and in their sensitivity to MTX when compared with M21 cells from an untreated mouse.

Inhibition of human renal cancer by monoclonal-anti-body-linked methotrexate in an ascites tumor model

The monoclonal antibody DAL K29 against a cell-surface antigen associated with a human renal cell carcinoma was covalently linked to the antifolate methotrexate with full retention of antibody activity and partial retention of drug activity. Using an ascites tumor model, developed after intraperitoneal (i.p.) inoculation of 5 x 10(6) cells of the human kidney cancer line Caki-1 per pristane-primed nude mouse, we showed that the methotrexate-Dal-K29 conjugate was a more potent tumor inhibitor (P less than 0.0005) of human renal cell carcinoma (which is resistant to currently available modalities including chemotherapy) than the drug or mAb alone, the drug linked to an isotype-matched nontumor-specific IgG or a mixture of the drug and the mAb. Only the conjugate could produce tumor-free survival in a proportion of the mice during the period of observation (i.e. 150 days after tumor inoculation).

Role of 1q trisomy in tumorigenicity, growth, and metastasis of human leukemic B-cell clones in nude mice

In order to investigate the association between various karyotypes of human tumor cells and biological behavior of tumors such as tumorigenicity, rate of growth, and the capacity to form metastasis, six chromosomally distinctive clones were isolated from an Epstein-Barr virus-transformed human chronic lymphocytic leukemic B-cell line which progressively grew and metastasized in irradiated nude mice. When inoculated into nude mice one clone (D10-1) with the karyotype of 46,XY,dup(1)(q11----q32) was more tumorigenic, grew faster, and produced more metastases than the other five clones. When mixtures of different clone-derived cells were grown in vitro or inoculated s.c. into nude mice the proportion of D10-1 cells was higher than their expected numbers in the cultures, s.c. tumors, and splenic and lymph nodal metastases. The growth and metastatic potential of the D10-1 clone were inhibited when cells from this clone were mixed with one or more clones that had slower growth. Duplication of 1q has been observed as a secondary aberration in human hematological malignancies and solid cancers. Our results demonstrate that duplication of the chromosome segment of 1q11----1q32 is associated with advantages in proliferation and metastasis formation.

Heteroconjugate antibody-directed killing of autologous human renal carcinoma cells by in vitro-activated lymphocytes

Tumor cell lysis can be enhanced significantly in vitro when heteroconjugate (HC) antibodies (anti-CD3 x anti-tumor mAb) are used to specifically direct lymphocyte effector cells to the tumor cell target. In order to effectively utilize HC antibodies in an immunotherapy protocol, methods must be identified for the optimum expansion, activation, and retargeting of lymphocyte-effector populations from cancer patients. In this study, we have compared the proliferative responses of different normal and renal cell carcinoma (RCC) patient lymphocyte preparations (PBL, tumor-infiltrating lymphocytes) stimulated in vitro for periods up to 12 days with a variety of growth factor combinations (anti-CD3, rIL-2, rIL-4). These activated lymphocyte preparations were then tested in vitro for their ability to kill RCC tumor cells and tumor cell lines in the presence of HC preparations (anti-CD3 mAb covalently linked to mAb reactive to different RCC tumor-associated Ag). RCC patient PBL cultured with anti-CD3 plus rIL-2 for 12 days resulted in a 3- to 160-fold expansion of effector cells. These cells, as well as tumor infiltrating lymphocytes, when retargeted with appropriate HC antibodies were capable of mediating high levels of killing of autologous tumor cells. No constitutive autologous anti-tumor cell response was detected in the absence of added HC antibodies. Of the five anti-RCC mAb tested (A6H, K29, K20, UR07, and URO 3), HC containing URO 3 x anti-CD3 and K20 x anti-CD3 elicited the highest level of tumor cell lysis by the activated lymphocyte effector cells. Together these results demonstrate that HC antibodies may be a useful imunotherapeutic reagent for directing the killing of RCC tumor cells by autologous lymphocytes.

Heteroconjugate antibody-directed killing of autologous human renal carcinoma cells by in vitro-activated lymphocytes

Tumor cell lysis can be enhanced significantly in vitro when heteroconjugate (HC) antibodies (anti-CD3 x anti-tumor mAb) are used to specifically direct lymphocyte effector cells to the tumor cell target. In order to effectively utilize HC antibodies in an immunotherapy protocol, methods must be identified for the optimum expansion, activation, and retargeting of lymphocyte-effector populations from cancer patients. In this study, we have compared the proliferative responses of different normal and renal cell carcinoma (RCC) patient lymphocyte preparations (PBL, tumor-infiltrating lymphocytes) stimulated in vitro for periods up to 12 days with a variety of growth factor combinations (anti-CD3, rIL-2, rIL-4). These activated lymphocyte preparations were then tested in vitro for their ability to kill RCC tumor cells and tumor cell lines in the presence of HC preparations (anti-CD3 mAb covalently linked to mAb reactive to different RCC tumor-associated Ag). RCC patient PBL cultured with anti-CD3 plus rIL-2 for 12 days resulted in a 3- to 160-fold expansion of effector cells. These cells, as well as tumor infiltrating lymphocytes, when retargeted with appropriate HC antibodies were capable of mediating high levels of killing of autologous tumor cells. No constitutive autologous anti-tumor cell response was detected in the absence of added HC antibodies. Of the five anti-RCC mAb tested (A6H, K29, K20, UR07, and URO 3), HC containing URO 3 x anti-CD3 and K20 x anti-CD3 elicited the highest level of tumor cell lysis by the activated lymphocyte effector cells. Together these results demonstrate that HC antibodies may be a useful imunotherapeutic reagent for directing the killing of RCC tumor cells by autologous lymphocytes.

Monoclonal antibodies against Epstein-Barr virus transformed B lymphocytes from a CLL patient

Immunization of BALB/c mice with EBV-CLL-1 cells, derived from Epstein-Barr virus transformed B lymphocytes from a chronic lymphocytic leukemia (CLL) patient, yielded 2 monoclonal antibodies (IgG1 Kappa and IgG2a Kappa) against a membrane antigen on a subset of normal B lymphocytes and non-Hodgkin's lymphomas. Immunofluorescence revealed strong reactivity of the antibodies with EBV-CLL-1 cells and with most lymphocytes in tonsil follicles, in the intestinal wall, around splenic arterioles and near Hassall's corpuscles in the neonatal thymus as well as with a small proportion of lymphocytes in some large reactive lymph node follicles, weak reactivity with 1/5 of peripheral blood B lymphocytes (PBL), and no reactivity with platelets, granulocytes and non-lymphoid tissues. PBL from 3 CLL patients showed weak staining of only larger cells. Intense fluorescence was observed in several non-Hodgkin's lymphomas of various histological types and in Burkitt's lymphoma lines but not in the 3 T lymphoblastoid and 12 nonlymphoid tumor lines examined. The antibodies precipitated Mr 22,000 and 33,000 bands from surface labeled RAJI or EBV-CLL-1 cells and cross-competed in a binding inhibition assay. The antibodies had approximately 6 million binding sites per EBV-CLL-1 or RAJI cell but were not cytotoxic. This high antigen-density and limited expression in normal cells may permit their use for immunocytological diagnosis and targeting cytotoxic agents and radionuclides against appropriate lymphoma cells.

Induction of MHC class II expression in recipient tissues caused by allograft rejection

MHC class II antigens (DR) are not commonly expressed on parenchymal cells of kidney and liver except when they are allografts undergoing rejection. The objective of this study was to determine whether allograft rejection can also induce DR upregulation in parenchymal cells of autologous recipient organs. Dogs had unilateral renal autografts to facilitate kidney sampling. All kidneys were tubular cell DR-negative. After 8-14 days each dog received a tubular cell DR-negative allograft. Tubular cell DR became positive in both allograft and autograft simultaneously, its onset and intensity correlating with blast cell infiltration and rejection in the allograft. Blast cells were first detected in the autograft after allograft nephrectomy, and then disappeared as autograft tubular cell DR diminished over the next 6-8 days. This was reproduced on repeat allografting. In 2 untreated dogs hepatocytes became positive on day 4, with no hepatic blast infiltrate. Four other dogs received cyclosporine immunosuppression. Allograft and autograft tubular cell DR, and hepatocyte DR, increased in all dogs, but were delayed while on CsA until onset of rejection despite transient earlier allograft blast infiltration. Downregulation in autograft and liver occurred together after allograft nephrectomy. An interferon-like substance appeared in plasma after allografting in association with the DR changes in native kidney and liver. Renal allorejection therefore induces upregulation of parenchymal DR expression in autologous liver and kidney of the recipient. It is probably mediated by an interferon-like substance derived from cells infiltrating the allograft. The effect is modified by CsA.

Synthesis of methotrexate-antibody conjugates by regiospecific coupling and assessment of drug and antitumor activities

In order to increase the retention of drug activity, regiospecific coupling has been used to synthesize conjugates of methotrexate (MTX, 1) with normal rabbit IgG (NRG) and a mouse anti-human renal cancer monoclonal IgG (Dal K-20). MTX gamma-methyl ester (4) was produced either by selective esterification of MTX or by coupling of 4-amino-4-deoxy-N10-methylpteroic acid (2) with suitable glutamic acid derivatives. The MTX gamma-methyl ester (4) was then converted to the corresponding hydrazide 6. An amide-linked conjugate was formed when the MTX gamma-hydrazide (6) was converted to reactive acylating species 7 by using tert-butyl nitrite or trifluoroacetaldehyde, which were reacted with nucleophilic centers, presumably epsilon-amino groups, in native IgG. A hydrazone-linked conjugate was formed when MTX gamma-hydrazide (6) was reacted directly with IgG that had first been oxidized with periodate to form polyaldehyde IgG. The regiospecifically synthesized conjugates were somewhat more effective inhibitors in vitro of dihydrofolate reductase and of colony formation by human renal cancer (Caki-1) cells than were control nonregiospecific conjugates.