Tissue distribution of rat macroglobulins in tumour-bearing rats.
Rat macroglobulins were determined in blood sera and extracts of tissues of intact rats and rats with Walker carcinoma by rocket immunoelectrophoresis. The serum levels of alpha1-macroglobulin (alpha1MG) alpha2-macroglobulin (alpha2MG) and pregnancy-associated alpha1-glycoprotein (alpha1PAG) were 1.86 +/- 0.07 mg/ml, 0.12 +/- 0. 02 mg/ml and 18.32 +/- 4.07 AU/ml respectively in control rats. Maximum concentrations of alpha1MG were found in heart, lung and spleen and lesser quantities were in liver and thymus, while alpha2MG and alpha1PAG were not found at all in tissue extracts from control rats. Serum alpha2MG and alpha1PAG concentrations increased more than 30-fold in tumour-bearing rats compared to control animals, while alpha1MG serum concentration was little changed. Increases in all three macroglobulins occurred in the tissues of tumour-bearing rats, particularly alpha1PAG. The tissue concentrations of alpha1MG and alpha2MG were similar and the tissue distribution was also similar with highest concentrations in heart and lung. Considerable quantities of the proteins were found in the tumour and part of peritoneum which made contact with the tumour. Changes in the protein concentrations in serum and tissue extracts of tumour-bearing rats suggest that all members of rat macroglobulin family are disturbed during the development of the Walker carcinoma, though only alpha2MG and alpha1PAG were substantially elevated. (+info)
Enhancement of migration inhibitory factor activity by plasma esterase inhibitors.
The plasma esterase inhibitors alpha2-macroglobulin, alpha1-antitrypsin, C1-inhibitor, antithrombin-heparin cofactor, and, as previously described, soybean trypsin inhibitor (Kunitz) and diisopropylphosphorofluoridate (9) enhance the response of guinea pig macrophages to migration inhibitory factor. To obtain this effect, macrophages are incubated with inhibitors prior to assay. The data suggest that (a) the enhancement of migration inhibitory factor response is due to the inhibition of esterases associated with the macrophage through a distinct active site on the inhibitors, and (b) that the active sites of antithrombin-heparin cofactor and soybean trypsin inhibitor, which interact with the macrophage enzymes, are different from the active sites of these inhibitors which interact with thrombin and trypsin respectively. Chemical modification of the active site of antithrombin-heparin cofactor for thrombin and of soybean trypsin inhibitor for trypsin does not affect their capacity to enhance the migration inhibitory factor response. From studies with thrombin, it was known that antithrombin-heparin cofactor has a heparin binding site. Addition of heparin was found to prevent the migration inhibitory factor-enhancing effect of antithrombin-heparin cofactor. The present results suggest that plasma esterase inhibitors may play a regulatory role in the response of macrophages to mediators of cellular immunity. (+info)
The effect of human alpha 2-macroglobulin on the restoration of humoral responsiveness in x-irradiated mice.
The effect of human alpha 2-macroglobulin on the recovery of the humoral immune response in X-irradiated mice has been assessed by measurement of antibody-forming cells in the spleen 5 days after challenge with sheep erythrocytes. The capacity of this protein to promote the recovery of immune responsiveness was variable, and appeared to be influenced by the strain and sex of the mice, and the dose of alpha2M given. (+info)
Dendritic cells transduced with full-length wild-type p53 generate antitumor cytotoxic T lymphocytes from peripheral blood of cancer patients.
Accumulation of wild-type or mutant p53 protein occurs in approximately 50% of human malignancies. This overexpression may generate antigenic epitopes recognized by CTLs. Because normal cells have undetectable levels of p53, these CTLs are likely to be tumor specific. Here, for the first time, we test the hypothesis that full-length wild-type p53 protein can be used for generation of an immune response against tumor cells with p53 overexpression. T cells obtained from nine HLA-A2-positive cancer patients and three HLA-A2-positive healthy individuals were stimulated twice with dendritic cells (DCs) transduced with an adenovirus wild-type p53 (Ad-p53) construct. Significant cytotoxicity was detected against HLA-A2-positive tumor cells with accumulation of mutant or wild-type p53 but not against HLA-A2-positive tumor cells with normal (undetectable) levels of p53 or against HLA-A2-negative tumor cells. This response was specific and mediated by CD8+ CTLs. These CTLs recognized HLA-A2-positive tumor cells expressing normal levels of p53 protein after their transduction with Ad-p53 but not with control adenovirus. Stimulation of T cells with Ad-p53-transduced DCs resulted in generation of CTLs specific for p53-derived peptide. These data demonstrate that DCs transduced with the wild-type p53 gene were able to induce a specific antitumor immune response. This offers a new promising approach to immunotherapy of cancer. (+info)
A monoclonal macroglobulin with antinuclear activity.
Serum containing a monoclonal IgM protein from a patient with Waldenstroms' macroglobulinaemia gave intense immunofluorescent staining of kidney nuclei. The Fab mu fragments of this immunoglobulin were obtained. The IgM and Fab fragments reacted in vitro with kidney nuclei using unfixed cryostat sections of rat or mouse kidney. After treatment of the patient with chemotherapy, the monoclonal IgM disappeared, and no more antinuclear activity could be detected in the serum. The results strongly suggest that this IgM protein had antinuclear activity. (+info)
Immunoglobulins and complement components in synovial fluid of patients with acute rheumatic fever.
Three components of complement and six other serum proteins were assayed in synovial fluid and serum samples from 25 patients with acute rheumatic fever in Trinidad. The resulting data indicate a relative decrease in both early and late components of complement within the synovial fluids which suggests local activation by immune complexes. Such activation of complement within the joint spaces may play a primary role in development of the inflammatory arthritis of acute rheumatic fever. (+info)
The low density lipoprotein receptor-related protein contributes to selective uptake of high density lipoprotein cholesteryl esters by SW872 liposarcoma cells and primary human adipocytes.
The concept that selective transfer of high density lipoprotein (HDL)-derived cholesteryl esters (CE) does not require lipoprotein internalization has been challenged recently by evidence that implicates HDL recycling during the selective uptake process. This has prompted us to examine the role of the low density lipoprotein receptor-related protein (LRP) in selective uptake. LRP is an endocytic receptor for lipoprotein lipase (LpL) and apolipoprotein E (apoE) ligands that are able to mediate selective uptake. We report that molecules that interfere with ligand binding to LRP, such as the receptor-associated protein (RAP), suramin, alpha(2)-macroglobulin, or lactoferrin, inhibit HDL-CE selective uptake by human primary adipocytes and SW872 liposarcoma cells by 35-50%. This partial inhibition of selective uptake from total HDL was not due to preferential inhibition of the HDL(2) or HDL(3) subfractions. Selective uptake by the scavenger receptor BI was not inhibited by RAP, excluding its involvement. Furthermore, in SW872 cells in which LRP was reduced to 14% of control levels by stable antisense expression, selective uptake was attenuated by at least 33%, confirming a role for LRP in this process. RAP, alpha(2)-macroglobulin, lactoferrin, and suramin (individually or in paired combinations) also attenuated selective uptake of HDL-CE by primary human adipocytes by about 40%. On the other hand, human skin fibroblasts express LRP abundantly but lack the capacity for selective uptake, demonstrating that other molecules are required. In SW872 cells, exogenous apoE or LpL can facilitate selective uptake but only the apoE-enhanced uptake can be inhibited by RAP, implicating apoE as a likely co-mediator. We discuss the possible mechanisms by which the endocytic receptor, LRP, can mediate selective uptake. (+info)
Variations in the level of a pregnancy-associated alpha-macroglobulin in patients with cancer.
The concentration of a pregnancy-associated alpha-macroglobulin (PAM) was determined in the blood of patients with various cancers. PAM was detectable in subjects with all types of malignant disease studied, and the level of the serum protein correlated well with the course of the disease: the concentration increased before clinical recognition of metastases and decreased significantly on successful treatment. Periodic PAM determinations may allow detection of tumour recurrence while it is still at a treatable stage and could aid in the evaluation of therapy. (+info)