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H Anundi

Publications and source records attributed to H Anundi.

23 records · Page 2Linked to original sources
PubMed1975

The subunit structure of thymus leukemia antigens.

EDTA-containing buffer solubilizes thymus leukemia antigens (TLa) from crude thymocyte membrane fractions. The TL antigens consist mainly of molecules of a size similar to immunoglobulin G when gel chromatography analyses were performed under physiological conditions. A single component of TLa was apparent on sucrose density gradient ultracentrifugation of solubilized thymocyte membrane macromolecules as monitored by indirect immunoprecipitation. The sedimentation constant for the TL antigens (5.8 S) was considerably less than that for immunoglobulin G. The gel chromatography and ultracentrifugation data suggest an apparent molecular weight for TLa of about 120000. TLa isolated by indirect immunoprecipitation is composed of two types of polypeptide chains. The smaller subunit was identified as beta2-microglobulin. The larger polypeptide chain carried the alloantigenic determinants and displayed a molecular weight of about 50000 after reduction and alkylation. TLa subjected to molecular weight determination under denaturing conditions was composed of two components. The smaller component was beta2-microglobulin which evidently is linked to the larger polypeptide chain by noncovalent interactions only. The larger component had a size greater than reduced and alkylated immunoglobulin G heavy chains. Upon reduction and alkylation of the latter component its size was reduced and it appeared to have a molecular weight of about 50000. Consequently, TLa is composed of two disulfide linked heavy polypeptide chains and two beta2-microglobulin molecules. TLa solubilized by papain digestion comprises two polypeptide chains, one of which is beta2-microglobulin. The larger 37000-dalton subunit is a fragment of the heavy polypeptide chain. This was demonstrated by digesting solubilized 120000-dalton TLa with papain. The proteolytic fragments obtained were indistinguishable from those directly released from the cell surface by proteolysis. The papain-derived TLa fragment exhibited most if not all the alloantigenic determinants.

Animals↗
PubMed1975

Evolutionary relationship between immunoglobulins and transplantation antigens.

The major human and murine histocompatibility antigens are tetrameric molecules with an apparent molecular weight of about 130,000. They are composed of two types of polypeptide chains. The two light chains, previously identified as beta2-microglobulins, are bound to the two heavy, alloantigenic HL-A or H-2 polypeptide chains by noncovalent interactions only. The heavy chains are held together by disulfide bridge(s) located in the part of the molecule that is attached to the cell membrane. By limited proteolysis of the histocompatibility antigens evidence was obtained suggesting that the heavy chain may consist of three compact domains connected by more extended stretches of polypeptide chain. Each domain appeared to contain a single disulfide bride encompassing about 60 to 70 amino-acid residues. Staphylococcus aureus protein A is known to bind exclusively to the Fe region of immunoglobulin G. It was, however, observed that protein A interacts in a similar way with the H-2 antigen heavy chain. This observation, together withthe homology of the primary structure of beta2-microglobulin to immunoglobulin G, the tetrameric structure of the alloantigens, the ogranizations of the heavy polypeptide chain into compact domains, and the presence of a single, immunoglobulin-like disulfide loop in each domain, establishes a close similarity in structure between histocompatibility antigens and immunoglobulins. The similarity in structural features suggests a common evolutionary origin of the two types of molecules.

Animals↗
PubMedDate not supplied

High performance concentration and gel filtration of rat urinary protein allergens.

Allergies to laboratory animals, notably rats, have become an increasingly recognized occupational problem. Identification and isolation of the individual proteins causing allergic reactions, could form the basis for early recognition of sensitivity, diagnosis, control of degree of pollution of the environment and desensibilization treatments. Frequently, allergens originate from dried rat urine. Because earlier published methods were found unsatisfactory we have developed a new strategy for isolation of rat urinary proteins including a high performance technique for their mild concentration on hydroxyapatite. The concentrated allergens have been fractionated according to molecular size by high performance gel filtration and according to carbohydrate content by wheat germ lectin-Sepharose 6 MB affinity chromatography. The obtained fractions have been examined by denaturing and non-denaturing polyacrylamide gradient gel electrophoresis followed by sensitive staining procedures, and tested with respect to allergenicity by skin tests on allergic patients.

Adult↗