Effect of concanavalin A treatment on the allogeneic response of mice to challenge with P 815 mastocytoma: interleukin 2 treatment reverses concanavalin A suppression in vivo.

Mice injected repeatedly with concanavalin A (Con A) prior to and following challenge with P 815 mastocytoma are suppressed in their cell-mediated cytotoxicity responses. Earlier studies showed that pretreatment of the animals with silica to affect macrophage (M phi) functions reversed the Con A suppression. In the present paper we have shown that peritoneal exudate cells (PEC) induced/activated by ip injection of Con A were able to transfer suppression to normal mice.

Suppression of cell-mediated immunity to challenge with P 815 mastocytoma in concanavalin A-treated mice.

C57Bl/6 (B6) mice allogeneic to the P 815 mastocytoma tumor cell line when treated with concanavalin A prior to and at frequent intervals following challenge intraperitoneally with 10(7) tumor cells showed a significant suppression of their cell-mediated immune response at 9-10 days when compared with untreated animals. Suppression of the immune response of mice syngeneic (DBA/2) or hybrid (BDF1) to the tumor was also evidenced by increased mortality rates in concanavalin A-treated animals. The suppression of cell-mediated cytotoxicity observed in B6 mice treated with concanavalin A could be reversed by pretreatment with 20 mg silica injected intraperitoneally 7 days prior to challenge.

Enhancement of experimental tumors in mice by treatment with concanavalin A.

Weanling BALB/c mice given injections of 300 micrograms concanavalin A (Con A) prior to and at frequent intervals after challenge with Moloney murine sarcoma virus (M-MuSV), 3-methylcholanthrene (MCA), or TEPC-15 plasmacytoma cells showed an enhancement of tumor induction or development. With the M-MuSV and MCA systems, this enhancement was evidenced by larger tumors and, in the MCA system, by more devastating tumors. Regression of the M-MuSV-induced tumors was more prolonged in Con A-treated mice.

Experimental conditions for obtaining suppressor and helper effects on the primary in vitro immune response by lymphocytes activated by polyclonal T-cell activators.

The effect of the polyclonal T-cell activators (PTA) Con A and PHA on the specific immune response to sheep red blood cells (SRC) was studied. Addition of PTA either enhanced or suppressed the anti-SRC response, and two variables were found to affect the results: time of addition of the PTA and the strength of the response in control cultures not given PTA. If the response was high, even suboptimal PTA concentrations induced suppressive effects, but if the control response was low, due to deficient batches of sera or because of the absence of serum, the addition of PTA increased the response or restored it to normal levels.

Functional heterogeneity of splenic T lymphocyte subpopulations. I. Determination of splenic subpopulations by the use of mitogneic probes.

The results reported here suggest that there exist two T-cell-mitogenic responsive populations in the spleen--one that is responsive to concanavalin A (Con A) and a second one that is responsive to Con A and phytohemagglutinin (PHA). Using an in vitro restimulation system, we have found that a primary in vivo activation with Con A effectively suppresses the subsequent restimulation response to PHA. However, in the reverse experiment, a primary in vivo PHA activation had little effect on the ability of cells to be restimulated with Con A.

Mechanism of action of suppressor cells. In vivo concanavalin-A-activated suppressor cells do not directly affect B cells.

The addition of a small proportion (10%) of in vivo concanavalin-A (Con-A)-activated spleen cells to normal spleen cell cultures suppressed the primary immune response to sheep erythrocytes (SRBC) but had no effect on the thymus-independent primary immune response to 3,5-dinitro-4-hydroxy-phenacetyl-conjugated lipopolysaccharide. When Con-A-activated cells were added after 24 h, there was no suppression of the anti-SRBC response but rather an enhanced response when few cells were admixed. Con-A-activated cells did not influence activation of normal cells by polyclonal T- and B-cell activators.

Unique teichoic acid isolated from the cell walls of a strain of Staphylococcus aureus.

Teichoic acid antigen extracted from cell walls of a strain of Staphylococcus aureus has been shown to have the unique structure of glycerolphosphate, with N-acetyl-d-galactosamine as the immunodominant substituent.

Immunity to staphylococcal infection in mice: effect of living versus killed vaccine, role of circulating antibody, and induction of protection-inducing antigen(s) in vitro.

Mice immunized by sublethal doses of living Staphylococcus aureus strains other than the Smith diffuse strain were significantly more resistant to challenge with the Smith diffuse strain than animals immunized with heat-killed organisms. The increased resistance observed was shown, by appropriate passive protection experiments with immune mouse sera, to be due to circulating antibody, probably of the IgM class. In addition, it was observed that strains of S.

Antibody response to Staphylococcus aureus in rabbits: sequence of immunoglobulin synthesis and its correlation with passive protection in mice.

Antibody in hyperimmune rabbit antisera specific for Staphylococcus aureus teichoic acid was shown to be associated with the IgM fraction. Treatment of such sera with mercaptoethanol destroyed its activity in passive mouse protection tests, whereas absorption with antirabbit IgG had no effect. Antibody response in normal rabbits immunized by a single or by three daily injections of a killed vaccine of S.

Relation of mucoid growth of Staphylococcus aureus to clumping factor reaction, morphology in serum-soft agar, and virulence.

The growth characteristics of several strains of Staphylococcus aureus in Brain Heart Infusion and in a modified Staphylococcus Medium No. 110 were compared. In the latter medium all of the strains studied showed an increased mucoid character.

RUNT DISEASE INDUCED IN NEONATAL MICE BY STERILE BACTERIAL VACCINES.

A form of runt disease has been produced in neonatal CF-1 and ICR mice by the repeated injection of 10(9) washed, autoclaved, saline-suspended staphylococci or streptococci. The most severely affected animals showed a marked decrease in lymphoid tissues and resembled grossly and microscopically animals suffering from the classical runt or wasting disease described by others. The timing of the initial antigenic stimulation was of importance, and animals started on their course of injections at an age of 48 hours or older showed no effect.