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Biomedical subjects

A E Reif

Publications and source records attributed to A E Reif.

At least 37 records · Page 2Linked to original sources
PubMed1977

Passive immunotherapy for mouse leukemias with antisera of "directed" specificity: synergism with the action of cyclophosphamide.

Antileukemia sera with "directed" specificity are produced by immunization of rabbits with mouse leukemia cells admixed with normal antigen blocking (NAB) serum. Addition of NAB serum to the leukemia cells inhibits production of antibodies to normal cell components and directs specificity toward leukemia cell antigens. The resulting antileukemia serum (ALK-NABS) was not sufficiently potent to produce more than moderate therapy in the standard L1210 leukemia therapy assay. When given together with noncurative doses of cyclophosphamide (CTX), ALK-NABS acts synergistically. It is most effective when given early after injection of the leukemia cells and prior to injection of CTX. Daily repeated injections of a given dose are more effective than a single injection of that dose. Most important, small doses of ALK-NABS produce a significant prolongation of lifespan in conjunction with CTX. Results of therapy for BW-A leukemia with ALK-NABS in conjunction with CTX were negative.

Animals↗
PubMed1976

Preparation and therapeutic potential of rabbit antisera with "directed" specificities for mouse leukemias.

Several immunization regimens for preparation of ALK-NABS were compared. One series of eight intravenous injections spaced over 5 weeks gave an ALK-NABS with potency and specificity that could be bettered only slightly by a second series of four injections spaced over 2 weeks, whereas a third series of injections was deleterious. Use of late immune antisplenocyte NABS for such immunizations produced ALK-NABS reagents with the highest in vitro specificity to leukemia cells relative to splenocytes after absorption, whereas early immune antisplenocyte NABS gave ALK-NABS with the highest antileukemia specificity relative to thymocytes. Therapy experiments with leukemias L1210 and BW-A showed increased survival times for isogeneic mice injected intraperitoneally with 10(3) (L1210 only), 10(4), and 10(5) (higher significance for L1210) cells, when ALK-NABS was given intraperitoneally in high dose on 4 or 5 successive days starting 1 day after inoculation of leukemia cells. In additional experiments with 10(5) cells given intraperitoneally, lower doses of ALK-NABS were progressively more effective with L1210 leukemia, producing some survivors without any apparent toxicity from the antiserum. In contrast, a similar experiment with leukemia BW-A was entirely negative. Addition of guinea pig serum to already excessive amounts of antiserum was not helpful.

Animals↗
PubMed1976

Enzymatic degradation of tumor cells damaged by antibody plus complement.

Rapid degradation of ascites tumor cells damaged by the action of antibody plus complement was found to be accomplished by all proteolytic enzymes active at physiologic pH that were tested. For three types of murine ascites tumor cells (Ehrlich ascites, sarcoma-180, and L1210 leukemia), this rate of degradation at low trypsin concentrations was proportional to a high power of enzyme concentration. This suggests that the simultaneous action of two or more enzyme molecules at adjacent cell surface sites is necessary. Cell degradation was assayed by determination of cell volume distribution with a Coulter multi-channel particle size analyzer. The present study may offer clues to in vivo mechanisms of cell degradation.

Animals↗
PubMed1975

'Sufficient' absorption--a quantitative method to replace 'exhaustive' absorption.

At present, the only guideline for removal of undesired reactivities from an antiserum is that no activity against the cross-reacting (undesired) antigens should remain after exhaustive absorption. Since this guideline sets no upper limit on the amount of undesired antigens required for an exhaustive absorption, waste of possibly precious material and of time in performing multiple sequential absorptions can result. To minimize the quantity of antigen and of experimental work required for an absorption, a quantitative approach is suggested: the antiserum is test-absorbed with various amounts of the undesired antigens, and antibody activity still present against these antigens is then tested. The results can be plotted as a curve by use of Reif's modification of the Von Krogh equation. Thus, the exact amount of undersired antigens sufficient to remove all detectable reactivity against these antigens can be determined. The procedure is termed 'sufficient' rather than 'exhaustive' absorption, to stress that only detectable amounts (rather than every last trace) of undesirable antibodies have been removed. The nomenclat re 'exhaustive absorption' gives no indication that any practical attempt to achieve it can hardly escape having the same limitations as 'sufficient absorption'; it is therefore suggested that the misleading non-quantitative nomenclature 'exhaustive absorption' be eliminated from immunological terminology. 'Sufficient absorption' has been applied to the absorption of undesired (blood group) antibodies from rabbit antisera to CEA.

ABO Blood-Group System↗
PubMed1975

Proportional absorption. A method for determination of the relative specificity of antisera prepared against cells.

Antisera prepared against a complex of antigens such as a tissue cell may produce a mixture of antibodies of different specificities, affinities and types. Proportional absorption permits determination of the comparative specificity of such antisera. It is performed by absorbing the antisera with an amount of absorbent proportional to the initial content of (usually undesired) antibody to this absorbent; the potencies of desired and undesired antibodies are then separately determined. The method has been used to determine the specificity of a conventionally raised rabbit anti-mouse leukaemia serum, relative to one prepared with leukaemia cells admixed with rabbit antiserum against normal mouse lymphocytes (to block normal antigen sites on the leukaemia cell inoculum). The latter antiserum was cells as compared to normal splenic lymphocytes.

Absorption↗