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L Makowka

Publications and source records attributed to L Makowka.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Genetic control of humoral immune response to xenografts. A monoclonal antibody that causes the hyperacute rejection of cardiac xenografts uses the genes in a native form].

The early phases of the rejection of xenografts exchanged between closely-related species are dominated by a vigorous humoral immune response. We have recently used a linkermediated polymerase chain reaction to generate Ig heavy and light chain specific cDNA libraries to examine the Ig gene control of a prototypic IgM monoclonal antibody, HAR-1, that causes the hyperacute rejection of hamster xenografts. Recombinant clones from the library were screened directly from bacterial colonies by PCR and the nucleic acid sequences of the clones established. Our results demonstrate that the HAR-1 hybridoma is encoded by Ig VH and JH genes in a germline configuration. Comparison of the cDNA sequence for HAR1-VH with the germline equivalent of the gene isolated from newborn LEW liver (provisionally designated VH1.1) showed that the two VH sequences share a nucleic acid identity of 99,3%. Similarly, the HAR-1 monoclonal uses a Ig JH gene that is 98,2% identical with the JH1 nucleic acid sequence available in the GenBank. The use of Ig VH and JH genes in a germline configuration is similar to that seen with polyreactive natural antibodies to infectious agents and autoantibodies. These humoral responses are thought to be the results of the stimulation of a T cell-independent subset of B cells, the B-1a/B-1b subset, that are responsible for producing antibodies that serve as a primitive humoral (natural antibody) defense mechanism against infectious diseases. Our results suggest that the humoral component of the rejection of xenografts in the hamster-to-rat model may represent the stimulation of this type of B cell antibody response by xenogeneic target antigens that share antigenic epitopes with bacteria and other infectious agents.

Animals↗
PubMed1995

Genetic control of the humoral immune response to xenografts. I. Functional characterization of rat monoclonal antibodies to hamster heart xenografts.

The rejection of cardiac xenografts in the hamster-to-rat combination is characterized by the production of IgM antibodies that result in the rapid loss of the graft. We have recently produced rat monoclonal antibodies (mAb) to hamster heart xenografts in an attempt to develop reagents for use in identifying the target antigens for this reaction and to study the nature of the genetic control of the humoral response. The monoclonals were created by the fusion of myeloma cells with splenic lymphocytes from LEW rat recipients of hamster cardiac xenografts. The hybridomas were screened for antibody production, reactivity to hamster cell surface antigens, and the ability to mediate hyperacute rejection of hamster heart xenografts. A panel of monoclonal antibodies has been identified that are capable of inducing hyperacute rejection. All of these mAbs are IgM and bind strongly to hamster vascular endothelium. None of the mAbs were lymphocytotoxic or bound to hamster lymphocytes or erythrocytes. Immunopathologic studies demonstrated that these mAbs react specifically with hamster vascular endothelium and mediate a complement-dependent humoral reaction leading to the destruction of the cardiac xenografts. One of the mAbs (designated as HAR-1) has been characterized in detail. HAR-1 detects antigens distributed in the vascular endothelium, epithelium of bronchi in the lung, small intestine, tubules of kidney, and selective components of lymphoid organs--e.g., the stromal cells of the spleen and thymic medullary epithelium. Western blot analysis of hamster heart proteins with HAR-1 showed multiple bands with two major bands migrating at 80 kDa and 48 kDa. Absorption of the HAR-1 antibody with 48 individual carbohydrate molecules demonstrated that the strongest reactivity of the antibody is with a sialyl-Lea carbohydrate antigen.

Animals↗
PubMed1995

Genetic control of the humoral immune response to xenografts. II. Monoclonal antibodies that cause rejection of heart xenografts are encoded by germline immunoglobulin genes.

The early phases of the rejection of xenografts exchanged between closely related species are dominated by a vigorous humoral immune response. We have recently used a linker-mediated polymerase chain reaction (LM-PCR) to generate Ig heavy and light chain-specific cDNA libraries to examine the Ig gene control of a prototypic IgM monoclonal antibody, HAR-1, that causes the hyperacute rejection of hamster xenografts. Recombinant clones from the library were screened directly from bacterial colonies by PCR and the nucleic acid sequences of the clones established. Our results demonstrate that the HAR-1 hybridoma is encoded by Ig VH and JH genes in a germline configuration. Comparison of the cDNA sequence for HAR-1 VH with the germline equivalent of this gene isolated from newborn LEW liver (provisionally designated VHHAR-1) showed that the two VH sequences share a nucleic acid identity of 99.3%. Similarly, the HAR-1 monoclonal uses a Ig JH gene that is 98.2% identical with the JH1 nucleic acid sequence available in the GeneBank. The use of Ig VH and JH genes in a germline configuration is similar to that seen with polyreactive natural antibodies to infectious agents and autoantibodies. These humoral responses are thought to be the result of the stimulation of a T cell-independent subset of B cells, the B-1a/B-1b subset, that is responsible for producing antibodies that serve as a primitive humoral (natural antibody) defense mechanism against infectious diseases. Our results suggest that the humoral component of the rejection of xenografts in the hamster-to-rat model may represent the stimulation of this type of B cell antibody response by xenogeneic target antigens that share antigenic epitopes with bacteria and other infectious agents.

Amino Acid Sequence↗
PubMed1995

Differential usage of the T cell receptor repertoire for allorecognition of heart, liver, and kidney grafts.

We have previously demonstrated that the immune response to cardiac allografts in the ACI-to-LEW rat strain combination involves a limited use of the TCR V beta gene repertoire. In the present study we analyzed the expression of V beta genes by T cells infiltrating kidney and liver allografts to test whether a limited use of the T cell receptor (TCR) repertoire is a common denominator for immune responses to allografts. Graft-infiltrating lymphocytes (GIL) were isolated from allografts on different days after transplantation and analyzed for the expression of V beta genes using a semi-quantitative polymerase chain reaction (PCR) without manipulations in tissue culture. We detected a limited expression of the V beta gene repertoire in fresh GIL harvested from both kidney and liver allografts early in graft rejection. The level of TCR repertoire usage, however, was influenced by the type of graft. The rejection of heart and kidney allografts was associated with more limited use of the V beta gene repertoire when compared with that seen for the rejection of liver allografts. The limited use of the V beta gene repertoire was only apparent when analyzed early in graft rejection; as the rejection reaction progressed T cells using a more diverse V beta repertoire infiltrated the graft. The limited use of TCR repertoire of the early T cell response to allografts may provide the opportunity to therapeutically disrupt the rejection reaction by targeting selected T cell populations for elimination at the time of organ transplantation.

Animals↗
PubMed1995

Structure and repertoire usage of rat TCR alpha-chain genes in T cells infiltrating heart allografts.

We have studied the structure and diversity of TCR alpha-chain genes used by graft-infiltrating lymphocytes (GIL) in the ACI-to-LEW rat cardiac allograft model. We previously reported the structure of 16 different V alpha and 17 different J alpha genes isolated in two different cDNA libraries established from LEW thymocytes and GIL. In this report, we obtained new sequence information for 17 additional V alpha and J alpha genes from the GIL cDNA library. This study completes our characterization of 33 different V alpha and 23 different J alpha genes in rats. The V alpha genes are classified into 14 different families. Nucleotide sequence comparison with mouse alpha genes revealed the existence of mouse homologues for all the J alpha and 32 of the 33 V alpha genes. One of the rat V alpha genes seemed to have no known mouse counterpart and is classified here as a V alpha 24 gene family. The definition of rat TCR alpha-chain genes derived from these studies should facilitate a better understanding of the T cell role in pathologic conditions including autoimmune diseases and graft rejection. As for the TCR alpha-chain repertoire usage in allograft rejection, we completed the characterization of 36 productively rearranged TCR alpha-chain cDNA clones from the GIL cDNA library and found 31 different V alpha and 23 different J alpha genes among these clones. Unlike the TCR beta-chain that uses a limited repertoire, the alpha-chain repertoire usage seems to be relatively more diverse in this allograft model. These results suggest that the interaction of beta-chain with allogeneic MHC-encoded determinants may dictate the T cell reaction to the heart allograft in this model.

Abdomen↗
PubMed1995

Peptides derived from alpha-helices of allogeneic class I major histocompatibility complex antigens are potent inducers of CD4+ and CD8+ T cell and B cell responses after cardiac allograft rejection.

We studied the rejection of cardiac allografts in a rat strain combination (PVG.R8 to PVG.1U) disparate for a single class I MHC antigen (RT1.Aa) to test the extent by which this molecule is recognized as peptides in association with recipient MHC molecules during graft rejection and the contribution of this recognition process to the rejection reaction. Three synthetic peptides that correspond to the portions of alpha-helices of the alpha 1 (P1, P2) and alpha 2 (P3) domains of the donor RT1.Aa molecule were used in this study. Splenocytes from heart allograft recipients at rejection responded in a proliferation assay to all 3 peptides and in a cytotoxic assay to peptides P1 and P2. The peptide-mediated proliferation and cytolytic reactions were blocked by antibodies against CD4/class II MHC and CD8 molecules. Serum from graft recipients at rejection contained significant titers of antibodies to peptides. Presensitization of graft recipients with the peptides resulted in a marked increase in peptide-mediated T cell and antibody responses. Although all 3 peptides were effective in eliciting active immune responses, the P3-mediated response was minimal when compared with those mediated by P1 and P2. Recipients presensitized with the peptides rejected their grafts in 5 days compared with 6 days for unsensitized animals. Recipients presensitized with donor-irradiated splenocytes and aortic endothelial cells, on the other hand, rejected their grafts in 1 and 3 days, respectively, which suggests that immunization with the whole RT1.Aa molecule is required to stimulate accelerated rejection of the graft. This rejection was associated with high titers of donor cell-specific antibodies that exhibited moderate cross-reactivity with the peptides. Our results clearly demonstrate that (1) the donor RT1.Aa molecule is recognized as peptides in the context of recipient class I and class II MHC molecules during the rejection of heart allografts, and (2) peptides derived from this molecule are highly immunogenic in that they contain epitopes recognized by CD4+ and CD8+ T cells and alloantibodies. Immune responses elicited by these peptides, however, did not significantly affect the rate of rejection. These results suggest that acute rejection of allografts may be mediated primarily by the direct recognition of intact MHC molecules.

Amino Acid Sequence↗
PubMed1995

Intragraft cytokine gene expression in human liver allografts.

Cytokines are thought to play an important role in the inflammatory and immune responses of allograft rejection. We evaluated the pattern of cytokine gene expression in 36 liver biopsy specimens obtained from 20 recipients of primary orthotopic liver allografts. Specific mRNA expression was identified by a polymerase chain reaction (PCR) using oligonucleotide primers specific for human interleukin (IL)-1 beta, IL-2, IL-4, IL-6, IL-10 Interferon (IFN) gamma, tumor necrosis factor (TNF)-alpha and beta-actin. We detected IL-1 beta, IL-6 and IFN-gamma cytokine message most consistently in patients with rejecting liver allografts. TNF-alpha and IL-2 were also observed in rejecting livers, but only during the early phases of the reaction. IL-4 was expressed in the majority of liver allograft biopsy specimens, regardless of the presence or absence of clinical or pathological evidence of rejection. Sequential biopsy specimens in rejecting allografts showed decreased cytokine expression after the induction of a positive response to immunosuppressive therapy. The analysis of biopsy specimens from stable liver grafts showed a predominance in the expression of IL-10. These results may reflect a differential production of inflammatory and regulatory cytokines in response to liver allograft rejection in transplant recipients. They suggest that three cytokines, IL-1 beta, IL-6 and IFN-gamma, may play an important role as markers for liver allograft rejection. Conversely, IL-10 expression was noted in patients with stable graft function. This pattern of expression may correlate with host immune responses that allow for prolonged, rejection-free survival of the graft.

Biomarkers↗
PubMed1995

Differential patterns of reaction of human natural antibodies to pig hepatocytes and vascular endothelium.

We have recently conducted a series of experiments to characterize the pattern of reaction of human natural antibodies (NA) with individual pig liver cells. Pooled normal human serum (PHS) was incubated with cultured pig hepatocytes (HEP), aortic endothelial cells (AEC), and portal endothelial cells (PEC), and the reaction of NA to different cell types was measured by antibody-mediated cytotoxic (MTT assay), antibody binding (ELISA), and flow cytometric analysis. The human NA displayed a differential pattern of binding with hepatocytes exhibiting a more limited expression of xenoantigen expression than either aortic or portal endothelial cells. These differences in reaction patterns were also noted for Western blot analysis of individual cell membrane extracts. Preincubation of the pig cells with anti-pig MHC antibodies did not inhibit the binding of human IgM natural antibodies to the pig cells. Comparison of the pattern of NA absorption following the use of bioartificial liver support in patients with acute hepatic failure demonstrated limited ability of pig hepatocytes to absorb substantial amounts of NA. These studies indicate that pig hepatocytes are less vulnerable to NA cytotoxicity than pig vascular endothelial cells and that pig vascular endothelial cells express xenoantigens that are unique and not found on hepatocytes.

Animals↗
PubMed1995

Malignant vascular tumors of the liver presenting as liver failure and portal hypertension.

We describe three patients referred for orthotopic liver transplantation with liver failure and portal hypertension who were found to have malignant vascular tumors: two patients with angiosarcoma and one patient with epithelioid hemangioendothelioma. Their clinical presentation mimicked decompensated chronic liver disease. None had tumor masses on computed tomography and ultrasonography. Massive tumor involvement of the liver was identified in the two patients studied by magnetic resonance imaging. Pathological examination of the explanted liver at the time of transplantation in one patient and autopsy in a second patient showed angiosarcoma. Laparoscopic liver biopsies in the third patient showed epithelioid hemangioendothelioma. The vascular origin of the tumor was established by histopathologic examination and confirmed with immunohistochemistry. Malignant vascular tumors of the liver should be included in the differential diagnosis of liver failure of unclear etiology.

Adult↗
PubMed1995

Failure of liver transplantation to diminish cardiac deposits of amylopectin and leukocyte inclusions in type IV glycogen storage disease.

Orthotopic liver transplantation has been used to treat glycogen storage disease type IV. Most long-term surviving patients who have undergone liver transplantation have been free of neuromuscular and cardiac morbidity, and regression of cardiac amylopectin infiltration has been reported after liver transplantation. Leukocyte inclusions in glycogen storage disease type IV have also been reported. We present the case of a child who underwent orthotopic liver transplantation for glycogen storage disease type IV. In contrast to previous reports, at autopsy 2 1/2 years after transplantation, there was massive amylopectin deposits in his heart. Further, peripheral leukocytes never showed loss of amylopectin inclusions after transplantation. Orthotopic liver transplantation for type IV glycogen storage disease may not, in all cases, result in improvement in other affected organs. Consideration of multiorgan transplantation appears warranted.

Amylopectin↗
PubMed1995

Detection of hepatitis C virus with RNA polymerase chain reaction in fulminant hepatic failure.

The role of hepatitis C virus (HCV) infection in fulminant hepatic failure is controversial. The frequency of serum HCV RNA positivity in previously reported patients with fulminant hepatic failure (FHF) of indeterminate cause ranged from 0 to 12% in the United States and Europe and from 43% to 59% in Asia. We assessed serum HCV RNA using polymerase chain reaction (PCR) and oligoprimers from the 5'UTR of the HCV genome in 26 consecutive patients with FHF. Another laboratory independently performed PCR on 21 of the serum samples using different oligoprimers from the 5'UTR and NS3 region of the HCV genome. Serum HCV RNA was detected in two of seven (28%) patients with hepatitis B, 9 of 15 (60%) with an indeterminate cause, and in none with hepatitis A (n = 2) or drug-induced hepatotoxicity (n = 2). HCV RNA PCR results were concordant between both laboratories in 17 of 21 (81%) of samples. In patients with an indeterminate cause, HCV RNA positivity was significantly associated with the transmission risk factor of low socioeconomic status and Hispanic ethnicity. Eighteen patients underwent liver transplantation (LT) and 15 (83%) survived. Among patients with FHF of indeterminate cause, recurrent or acquired HCV infection after transplantation occurred in three of five (60%) and one of four (25%) patients, respectively. Three of four (75%) patients with hepatitis C virus infection post-LT also developed histologic hepatitis. HCV appears to be the causative agent of a substantial number of cases of FHF classified as indeterminate in the Los Angeles area. Differences in patient populations or risk factors may explain the discordant incidences of HCV infection in FHF observed among different programs.

Adolescent↗
PubMed1995

Hepatic resection for malignancy in the elderly.

Although elderly patients are accounted for in all large series of major hepatic resections, the role of age as a determinant of outcome remains unclear. At Cedars-Sinai Medical Center, we review a series of 20 major hepatectomies for neoplasia performed in patients older than 66 years of age (4 of them > or = 80 years old) over a 5-year period. A retrospective comparison was conducted with a group of 22 hepatectomies for malignancy performed in 20 patients younger than 59 years of age during the same time period. The younger group had a significantly greater degree of liver resected (12 trisegmentectomies vs 3). Although one operative death (5% mortality) was observed in the elderly group, no statistically significant difference was noted, when compared to the younger group (Chi-square, P = 0.48). Likewise, no significant difference in the complication rate (20% vs 33%) was noticed (Chi-square, P = 0.8). Severe postoperative liver dysfunction was present in 2 cases (10%) in the elderly group and one (4%) in the younger group. These patients underwent a right trisegmentectomy (TS). Nine patients from each group were resected without red blood cell transfusion. We conclude that major hepatic resection in elderly patients without severe comorbid disease is a safe procedure that is not associated with an increased perioperative morbidity or mortality rate.

Age Factors↗
PubMed1994

Prevention of orthotopic liver allograft rejection in rats with a short-term brequinar sodium therapy. Analysis of intragraft cytokine gene expression.

Brequinar sodium (BQR) is a new immunosuppressive drug that is highly effective in preventing graft rejection in several different experimental settings, including primary allografts and xenografts. A short course of BQR treatment during the onset of allograft rejection can induce the permanent survival of liver and kidney allografts in rats. To study the molecular basis of BQR-induced prolongation of allograft survival, we analyzed the intragraft pattern of IL-1 alpha, IL-2, IL-2R, IL-4, IL-6, IL-10, and TNF gene expression in the ACI-to-LEW liver allograft model. A semiquantitative polymerase chain reaction was developed to measure cytokine gene expression in control and BQR-treated liver graft recipients at various days after transplantation. Untreated control liver allografts expressed all of the cytokines analyzed. There was a marked increase in the steady state level of transcripts for each cytokine as graft rejection proceeded. The treatment of liver graft recipients with 12 mg/kg/day of BQR on days 6, 7, and 8 after transplantation suppressed the expression of all these cytokines within 24 hr of administration. The early suppression of cytokine expression was associated with a modest but distinct reduction in the infiltration of inflammatory cells into the liver grafts. The reduction in the level of transcripts for IL-4, IL-6, and IL-10 persisted in long-term survivors (30 days after transplantation). In contrast, there was a significant increase in the level of transcripts for IL-1 alpha, IL-2, and IL-2R in these long-term survivors. Our results demonstrated clearly that the pattern of cytokine gene expression during allograft rejection is significantly altered by a 3-day course of therapy with BQR. The temporary down-regulation of cytokine gene expression may be responsible for an altered immunological state that results in the prolonged survival of liver allografts.

Animals↗
PubMed1994

Acute liver failure due to lymphoma. A diagnostic concern when considering liver transplantation.

Lymphomatous involvement of the liver may present as acute liver failure but is an absolute contraindication for liver transplantation. Therefore it is imperative to diagnose such patients since survival in this group is poor and recurrence is high. We describe two patients with acute liver failure referred for liver transplantation whose diagnostic testing revealed hepatic lymphoma. These cases underscore the importance of considering lymphoma in the differential diagnosis of acute liver failure prior to liver transplant.

Adolescent↗