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Biomedical subjects

W D Linscott

Publications and source records attributed to W D Linscott.

At least 19 recordsLinked to original sources
PubMed1981

The bovine complement system.

Methods were developed for titrating bovine C3b-inactivator, C2, C3 and C4 by non-hemolytic means, and for assaying by hemolysis all the components of the bovine classical complement system except C2. All components were detected at serum dilutions above 1:1000, and some at dilutions above 1:100,000. C1, C4, C5, C7 and C9 titers were very high in adult bovine serum, and C2 and C8 were relatively low. C1, C2, and C8 were quite heat-labile at 56 degrees C, and C7 was moderately so, while C3 amd C6 titers increased after heating due to inactivation of a heat-labile inhibitor. Fetal bovine serum contained approximately 1-3% of adult levels of conglutinin, C1 and C6, and 5-50% of adult levels of the remaining components except C3. C3 antigen was found, but C3 functional activity was undetectable in most fetal bovine sera, though present at low levels in a few.

Animals↗
PubMed1979

A sensitive hemolytic assay for mouse C3.

We have developed a sensitive hemolytic assay for mouse C3, utilizing readily available guinea pig complement components and standard techniques, which allows C3 to be detected in mouse serum diluted many thousand-fold. Mouse serum also contains a potent, relatively heat-stable C3-inactivator system, which is largely blocked by Suramin.

Animals↗
PubMed1978

A specific indicator for mouse lymphocyte C3b receptors.

IgM-sensitized sheep E bearing guinea pig C4 and C3b (EAC43bgp) react as strongly with mouse spleen cell C3b receptors as do optimally prepared EACmo. Yet, when the C3b is converted to C3d by incubation with heated serum at low ionic strength, reactivity with mouse spleen cells is completely lost whereas binding to guinea pig spleen cells remains high. It is concluded on the basis of this and other evidence that EAC43bgp are a sensitive and specific indicator for mouse lymphocyte C3b receptors. Degradation of the C3b on these cells will not cause misleading binding to C3d receptors, as could occur with cells bearing mouse C3b.

Animals↗
PubMed1978

Evidence that bovine conglutinin reacts with an early product of C3b degradation, and an improved conglutination assay.

When EAC43b were treated with heated serum in EDTA, reactivity with bovine conglutinin appeared rapidly, even at 0 degrees C, and almost simultaneously with the loss of C3b rosetting capacity. At the time conglutinability first appeared, there was no detectable decrease in I-A or hemolytic C3 activity, and no detectable C3 antigen release from the cells. With prolonged exposure to heated serum in EDTA, I-A (immune adherence) and hemolytic C3 activity were lost. If this exposure was at 37 degrees C, C3 antigen became strongly detectable in the supernatant fluid, and eventually conglutinability was markedly reduced or lost, whereas C3d rosettes were unaffected. We suggest that bovine conglutinin reacts with some early product of C3b degradation, rather than with C3d, and propose that this intermediate be designated C3k. We have developed a semi-quantitative assay for bovine conglutinin, utilizing a Coulter Counter to register the decrease in total particles due to red cell aggregation. By using this method, we have detected conglutination with mouse complement (C) as well as with that from man and the guinea pig.

Animals↗
PubMed1977

Improved efficiency of mouse, guinea pig and human C3b inactivator at low ionic strength, and reproducible immune-adherence with mouse complement.

Inactivation of homologous C3b by heated guinea pig, mouse and human serum was found to be much more rapid and complete at low ionic strength (0.037) than at micron = 0.15. The C3b inactivator in human and mouse serum was somewhat unstable to heating at 56 degrees C. Heated guinea pig serum showed the greatest ability to inactivate heterologous C3b, and human serum the least. Suramin (1 mg/ml) completely blocked homologous C3b inactivation by heated human, guinea pig and mouse serum, and 0.1 mg/ml was effective with mouse but not with human or guinea pig serum. Immune-adherence reactions with mouse C3 produced somewhat unstable hemagglutination patterns, which were improved by using ovalbumin in the buffer and minimizing EAC exposure to warm temperatures. A prozone phenomenon was frequently observed in immune-adherence hemagglutination with mouse C3, and less frequently with guinea pig and human C3.

Animals↗
PubMed1975

The complement system in cryoglobulinaemia. Interaction with immunoglobulins and lipoproteins.

Serum from a patient with an IgM-lipoprotein cryoglobulin, both before and after removal of the cryoprecipitate at 0 degrees C, had extremely low levels of whole complement (C), C1, C4 and C2, while amounts of the remaining components were normal or only slightly reduced. The cryopredipitate, when added to fresh normal human serum, reproduced this pattern of C fixation. Separation of the patients's serum at 37 degrees C into its lipoprotein, IgG and IgM fractions revealed that the IgM alone would precipitate at 0 degrees C. This precipitation was unaffected by the patients's IgG, but was markedly enhanced by extremely small amounts of the patient's d less than 1-075 lipoprotein fraction or of homologous very low density lipoprotein (VLDL). Aggregation occurred even at 37 degrees C in the presence of VLDL. Fixation of semi-purified human C1 paralleled these results closely: it occurred with the patient's IgM alone at 0 degrees but not at 37 degrees C, while IgM in the presence of the patient's lipoprotein, or of VLDL from normal serum, fixed C1 strongly at 37 degrees as well as at 0 degrees C. Fab dimers and monomers prepared from the patient's IgM did not aggregate in the cold, even in the presence of lipoprotein, and did not inhibit the aggregation of intact IgM in the presence of VLDL, at any temperature. All three highly purified IgM cryoglobulins, and three of four IgG cryoglobulins, fixed C1 strongly. The IgG preparation which failed to fix C1 was the only one which had lost its cryoprecipitability during purification. Measurement of C3 or whole C levels may be an insensitive method for detecting C fixation in cryoglobulinaemia. It is suggested that analysis for C1, C4 or C2 should be employed instead.

Aged↗
PubMed1975

EAC4 and EAC14 production without purified Ci.

EAC4 and EAC14 of high activity were prepared by treating sensitized red cells with human or guinea pig serum in the presence of TTHA, a chelating agent whid at low pH to maximize C1 and C4 activity and to minimize C3 contamination. Cells prepared with guinea pig complement were contaminated with C2, which could be decayed away at 37 degrees C. Cells sensitized with IgG antibody were more reactive than those sensitized with whole serum or with IgM, and preparations made with TTHA-complement were more reactive than those prepared with purified C1 plus EDTA-complement. EAC14 stored at 0 degrees C for 3 weeks lost very little activity.

Animals↗