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The existence of disulfide-bonded immunoglobulin (Ig) complexes of IgM-IgA, IgM-IgG, and IgM-IgG, in addition to a monoclonal IgM (kappa) paraprotein, free kappa chains and fragments of IgG (FIgG), were found in the plasma of a multiple gammopathy patient. This is the first report on the interclass disulfide-bonded Ig complexes. Upon exposure to a dissociating buffer containing 6 M urea, 0.1 M Tris-HCl, pH 8.0, a small portion of the IgM-IgA complexes and most of the IgM-IgG as well as the IgM-FIgG complexes dissociated, but the majority of the IgM-IgA and small amounts of other complexes remained intact. These intact complexes were not the result of antigen-antibody reactions and were apparently held together by disulfide bonds which could be broken into monomeric Ig basic units (H-L)2 and smaller components by mild reduction and alkylation.

A study of the uridine monophosphate kinase (UMPK) electrophoretic patterns in Venezuelan individuals from the mestizo population of Caracas and from the Warao Indians of the Nabasanuka village in the Delta of the Orinoco River are reported. Among the mestizo population, the frequency of the UMPK1, UMPK2, and UMPK3 alleles was .979, .020, and .001, respectively. A higher frequency of the UMPK3 gene was seen in the highly inbred Warao Indians than any other population studied to date.

1. Starch gel electrophoretic patterns and activity of red cell UMP-kinase were compared in different species of vertebrates. 2. A characteristic electrophoretic pattern for each species of animal studied was found. 3. The mammals differed markedly from the rest of the vertebrate compared in having a faster electrophoretic migration. 4. Significant species differences in total UMPkinase activity could be observed.

Immunochemical studies are described in an unusual case of Waldenström's macroglobulinemia. Two monoclonal Igs (whole IgG1/kappa and IgG1/kappa half molecules) occurred in the serum in addition to the IgM monoclonal protein. Protein electrophoresis of the serum showed a monoclonal component in the gamma region, and the immunoelectrophoresis allowed detection of a monoclonal IgM/kappa and another abnormality represented by a double precipitin line in serum and urine, observed when antiserum anti IgG was used. The abnormal proteins were purified and further analyzed. The IgG-related proteins were whole four chains IgG monoclonal molecules, 1/2 IgG monoclonal molecules, composed of one heavy and one light chain, and residual polyclonal IgG. The half molecules were antigenically deficient with respect to normal IgG. The idiotypic analysis showed that the three monoclonal proteins shared idiotypic determinants. This patient had clinical and morphological findings of Waldenström's macroglobulinemia and, as observed in other cases, the formation of half molecules was not associated with a distinct clinical syndrome.

Three phenotypical variants of normal human serum alpha2-macroglobulin revealed by immunoelectrophoresis and specific antibodies obtained in rabbits are presented. The variants are characterized by differences in electrophoretic mobility: one being fast, one slow, and one of an intermediate rate. To find out possible differences with respect to the effect of the trypsin and chymotrypsin on the three variants, they were treated with the enzymes before immunoelectrophoresis. Migration was accelerated in all cases, after complexing with the enzymes, but the differences in the relative positions of the variants were maintained. The trypsin- and chymotrypsin-binding capacities of these three forms seem to differ, as suggested by the results presented in this report.

A study is presented of bovine foetal albumin, a serum protein present in newborns less than 15 days old. As a result of the biochemical and immunochemical analyses, and of the comparison carried out with human foetal albumin, it was concluded that: 1) They share certain characteristics, such as molecular weight, behaviour in the presence of reducing agents, and a great affinity for staining agents. 2) Bovine foetal albumin has a slower electrophoretic mobility than that of the corresponding adult albumin, this aspect differentiating it from human foetal albumin which is faster than human adult albumin.

UMPK 3 is a rare variant of the polymorphic enzyme of human red cells, uridine monophosphate kinase. This homozygote phenotype was detected among the Warao Indians of Venezuela. The UMPK 1 and UMPK 3 enzymes were partially purified following the method described by Tend et al. (1976). The biochemical and kinetic parameters of both variants were studied in crude hemolysates and in partially purified enzymes. A comparison was made with the results previously reported by Teng for UMPK 1 and UMPK 2, and it was concluded that UMPK 3 seems to resemble the other two allelic gene products in Km values for UMP, CMP, and ATP but differs from them in electrophoretic mobility, pH optimum, and thermal stability.

A new case of IgE/K myeloma in a 38-year-old male is described. The clinical course, bone marrow picture and serum electrophoretic pattern were typical of multiple myeloma. Heating of the serum at 56 degrees C induced an irreversible gel formation or pyroglobulin that was isolated and proved to be identical to the IgE paraprotein, by biochemical and immunochemical methods. The thermoprecipitability was abolished by treatment with urea, sodium dodecyl sulphate and neutral salts and not inhibited by sugars, alcohols, 2-beta-mercaptoethanol and guanidine HCl. The association of an IgE myeloma protein with a pyroglobulin is a finding not previously reported in a myeloma of this class.

The serum of a patient with a clinically and immunologically identified multiple myeloma of the IgE class was found to contain both IgE-albumin and IgG-albumin complexes. These complexes were partially purified and some of their properties studied by biochemical and immunochemical methods. The IgG-albumin interaction was dissociated by 5.0 M guanidine hydrochloride, while the IgE-albumin interaction was dissociated upon reduction by mercaptoethanol, suggesting that the proteins were linked by intermolecular disulfide bonds. Complex formation between pathological or normal immunoglobulins with albumin have been reported for IgG, IgM and IgA but not for IgD or IgE. The present observation seems to be the first in which an IgE myeloma protein was involved.

Two cases of alpha chain disease are described. The clinicopathological features of the two patients were very similar, and similar to the numerous cases described in the literature, presenting the gastrointestinal form of the disease. In both patients the pathological protein was not noticeable in the electrophoretic pattern. The diagnosis was established by immunoselection with electrophoresis. The alpha-HCD proteins belonged to the alpha 1 subclass and in no case was it found in the urine. The patients were young Venezuelan mestizos and seem to be the first cases reported in Venezuela.

Fetal and adult bovine albumins were isolated and compared with the commercially obtained fraction V of Cohn, in terms of their ability to support cell proliferation, when added as a supplement to serum-free lymphocyte cultures activated with phytohemagglutinin. It was found that fetal albumin is the least efficient of the three proteins in permitting lymphoproliferation. A difference between the kinetics of proliferation of lymphocyte cultures supplemented with albumin and with serum was also observed.