Serum's lymphocyte immunoregulatory factors (SLIF)

Modulation of bovine mononuclear cell proliferation during physiological transitions of the mammary gland

Mammary secretions and blood were collected from five primiparous Holstein cows 14 d following cessation of milking and 14 d prior to parturition for preparation of serum and mammary secretion skim fractions. Mammary secretions and blood were collected from the same animals 15 to 18 d following cessation of milking and 2 to 13 d prior to parturition for isolation of mononuclear cells. Effects of serum on mammary gland mononuclear cell proliferation and skim fractions from mammary secretions on blood mononuclear cell proliferation were evaluated. Mononuclear cell proliferation was evaluated in a mitogen-induced lymphocyte proliferation assay and in a mixed leukocyte assay. Proliferative responses of blood and mammary gland mononuclear cells did not vary significantly between the two time periods evaluated. Mammary secretion skim fractions obtained at both time periods significantly suppressed blood mononuclear cell proliferation. In contrast, exogenous serum enhanced mammary gland mononuclear cell proliferation in response to mitogens and allogeneic cells. Ability to enhance in vitro proliferation of mammary mononuclear cells isolated during physiological transitions of the mammary gland may suggest the potential for enhancing mammary mononuclear cell proliferation in vivo to reduce incidence of new intramammary infections at times when the mammary gland is highly susceptible.

Suppression of lymphocyte blastogenesis by sera from calves transported by road

The effect of sera from 4-h road-transported calves on mitogen-induced blastogenesis of bovine lymphocytes was investigated. Sera collected just after transportation showed a significant suppression (P less than 0.05) on blastogenesis. The immunosuppressive activity was reduced from those sera when they were treated with dextran-coated charcoal. Fractionation of the sera by ultrafiltration revealed that the activity was mainly concentrated in the fractions of molecular weights less than 50 kD.

Propionibacterium acnes immunotherapy in chronic recurrent canine pyoderma. An adjunct to antibiotic therapy

In a randomized, double-blind, placebo-controlled study, dogs with chronic recurrent pyoderma were treated with antibiotics plus intravenous injections of either Propionibacterium acnes or placebo. Responses (an increase, decrease, or clearing of lesions) were measured and evaluated statistically. Eighty percent (12 of 15) of the dogs treated with antibiotics and P acnes compared with 38% (five of 13) of the dogs treated with antibiotics and placebo responded with significant improvement or complete remission of lesions at the end of the 12-week treatment schedule (P less than 0.05).

Effect of serum on lymphocyte blastogenesis. 2. Characterization of disease-induced immunosuppressive factors by chromatography and molecular weight determination

Numerous infectious and noninfectious diseases are associated with the appearance of suppressive serum lymphocyte immunoregulatory factors (SLIFs). The suppressive SLIFs in sera from clinically healthy dogs and from dogs with bacterial (staphylococcal, brucellar) or mycotic (blastomycotic) infections were further characterized by dialysis, fractionation by ultrafiltrations and HPLC (high performance liquid chromatography) sieving, by affinity chromatography on protein A-Sepharose columns, and by DEAE-cellulose ion exchange chromatography. Factors of various molecular weights and of various elution patterns from DEAE-cellulose and affinity chromatography columns were taking part in the suppressive action of the whole serum. The 'common' inhibitors present in all sera were in the molecular weight range of 28 to 35 Kd, whereas the disease-induced suppressive SLIFs were present in various molecular weight categories. 'Common' suppressor SLIFs and some SLIFs from dogs with staphylococcal infections were partially dialysable; suppressive SLIFs induced in dogs with generalized brucellosis and blastomycosis were not dialysable. Protein A bound suppressive SLIFs from two of three dogs with staphylococcal pyodermas. DEAE-cellulose chromatography gave variable elution patterns with different animal sera. It is concluded that various suppressive SLIFs contribute to the immunosuppressive effect of the whole serum and no disease-specific suppressive SLIF could be identified.

[Lymphocyte markers in domestic animals. I. Mitogenic lectins and non-mitogenic lectins]

The authors reviewed the lymphocyte markers in domestic animals. The first part is devoted to lectins. The general and methodologic aspects of lectins as mitogens are studied. The main mitogen lectins are emphasized in regard to their field of utilisation and the technical aspect of their use. The non-mitogen lectins are presented for cell suspension or tissue section staining.

Ascaris suum infection in pigs sensitizes lymphocytes but suppresses their responsiveness to phytomitogens

The effect of Ascaris suum infection and treatment with fenbendazole on the blastogenic response of peripheral blood lymphocytes to A. suum antigens and to three phytomitogens was assayed by the lymphocyte transformation technique. Repeated infections with A. suum led to the development of sensitized lymphocytes primarily responding to egg hatching fluid antigen. Treatment with fenbendazole decreased the number of specific sensitized lymphocytes, but favorably increased the resistance of pigs to reinfection. Immunity to reinfection did not correlate with the strength of the blastogenic response to A. suum antigens. Repeated infection with A. suum negatively affected the development of the blastogenic response to phytomitogens in the pigs, leading to a partial depression of the responsiveness of lymphocytes and to the partial suppression by serum. Responses to pokeweed mitogen were affected more than the responses to concanavalin A and phytohemagglutinin.

Effect of serum on lymphocyte blastogenesis. I. Basic characteristics of action by diseased dog serum

The immunoregulatory effect of serum on phytomitogen-induced lymphocyte blastogenesis was studied in 4 sera from diseased dogs and 1 serum from a clinically healthy dog. The results indicated that: (1) Each of the diseased animals responded to the given infection with a specific pattern of blastogenesis inhibition. (2) The blastogenesis suppression in vitro was proportional to the content of the suppressive serum in the medium. (3) A simultaneous presence of the mitogen and the suppressing "serum's lymphocyte immunoregulatory factors" (SLIF) was necessary for inducing blastogenesis suppression. (4) The suppressive sera most probably acted directly on the cells. (5) The final effect of the sera on lymphocyte blastogenesis was a result of an orchestrated action of blastogenesis-supporting, augmenting, and suppressing SLIF cooperating with the mitogen. (6) The suppressive pattern varied with the individual peripheral blood lymphocytes populations used in the test. (7) The blastogenesis-suppressing SLIF was heat-stable, noncytotoxic, and was not or only partially removable by absorption with peripheral blood lymphocytes. (8) The testing of SLIF activities required the use of various animal lymphocytes and a relatively complex setup of mitogens and control serum combinations for correct interpretations.