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M E Medof

Publications and source records attributed to M E Medof.

5 recordsLinked to original sources
PubMed1979

Suppressor cell function in multiple sclerosis: correlation with clinical disease activity.

Concanavalin A (Con A)-activated suppressor cell activity was determined in multiple sclerosis (MS) patients who had been assigned to one of three subgroups, those with active disease, those recovering from a flare-up, and those with stable disease. The level of suppression induced by the Con A-activated suppressor cells on the mitogenic response of autologous peripheral blood lymphocytes was reduced in patients with active disease (3 +/- 8%) compared with stable patients (30 +/- 8%), patients recovering from a flare-up (62 +/- 5%), and controls (40 +/- 5%). As a measure of the actual amounts of suppressor factors released, the effect of supernatants from the Con A-activated cells on the proliferative activity of a dividing cell line (L cells) was determined concurrently. The inhibitory effect of supernatants from activated cells was reduced in active and stable MS patients (7 +/- 3%) compared to controls (21 +/- 4%). Three of 4 with active MS showed mildly elevated immune complex levels as measured by the Raji cell technique; each of these patients had low suppressor activity. Levamisole (1 microgram per milliliter) failed to alter suppressor cell activity in our in vitro system.

Concanavalin A↗
PubMed1977

Characterization of DNA used to assay sera for anti-DNA antibodies; determination of the specificities of anti-DNA antibodies in SLE and non-SLE rheumatic disease states.

Commercial 14C-labeled KB cell DNA, widely used to assay sera for anti-DNA antibodies, was chromatographed on benzoylated-naphthoylated-DEAE-cellulose (BNDC) and on hydroxyapatite (HAP). On BNDC, only 25% of the 14C label eluted with 1 M NaC1 (KB fraction I) characteristic of ds-DNA. Fifty-five percent of the label eluted with 50% formamide-1 M NaC1 (KB fraction II) characteristic of ss or denatured DNA. On HAP, however, none of the 14C label eluted with 0.2 M phosphate buffer as anticipated for ss-DNA, but, rather, all of the 14C label eluted with 0.4 M phosphate, characteristic of ds-DNA. after pretreatment with S1 endonuclease of Aspergillus oryzae, which selectively digests ss regions, however, 42% of the 14C label was lost from the 0.4 M phosphate peak. These results indicated that more than half of this 14C-KB-cell DNA preparation was ds-DNA with ss regions which was undetectable by HAP chromatography. 3H-ds-DNA and circular 3H-ss-DNA prepared from T7 and phiX174 bacteriophage, respectively, were found to be chromatographically pure on both BNDC and HAP. None of 10 non-SLE sera (rheumatoid arthritis 3, mixed connective tissue disease 4, scleroderma 1, ulcerative colitis 1, and pulmonary fibrosis with chronic active hepatitis 1), previously believed to contain anti-ds-DNA antibodies on the basis of KB cell DNA testing and detectable antibodies against KB fraction 1 or T7 DNA: all of 10 KB cell DNA positive SLE sera had antibodies against both. Additionally, none of the 10 non-SLE sera had antibodies against KB cell DNA when retested with DNA that had been pretreated with S1 endonuclease. Seven of these 10, however, as well as all 10 SLE sera, had antibodies against phiX174 DNA, KB fraction II DNA and alkali-denatured T7 DNA. The data support the conclusions that 1) false positive tests for anti-ds-DNA antibodies can result from contamination of ds-DNA with ds-DNA having ss regions, and 2) non-SLE sera do not contain antibodies specific for ds-DNA at levels comparable to those found in SLE sera but rather contain high levels of antibodies reacting with ss regions or mixed DNA.

Antibodies↗