Interaction of a common cellular transcription factor, ATF, with regulatory elements in both E1a- and cyclic AMP-inducible promoters

We have previously identified a cellular transcription factor, ATF, which is involved in the expression of multiple adenovirus E1a-inducible genes. Here we show that ATF also binds to regulatory elements in cellular cAMP-inducible promoters. In these cellular promoters, ATF binds to a consensus sequence that has been previously shown to be necessary and in some instances sufficient for cAMP-inducible transcription. Furthermore, we show that binding of ATF to these promoter elements is required for the constitutive in vitro transcriptional activity of the cAMP-inducible somatostatin gene. Taken together, our results suggest that a common cellular transcription factor, ATF, can be regulated in vivo by two apparently unrelated inducing agents: the adenovirus E1a protein and cAMP.

Reflex bronchospasm-induced acute massive pulmonary collapse

Acute massive pulmonary collapse following reflex bronchospasm is described in a patient undergoing general anesthesia. The authors suggest that a chest radiograph should be taken as routine procedure after the onset of airway constriction during anesthesia.

Suppression of cytolytic T-cell activity by staphylococcal enterotoxin B-induced suppressor cells: role of interleukin 2

We have previously shown that staphylococcal enterotoxin B (SEB) is a potent inducer of suppressor T cells which function to inhibit antibody production in vitro. In the present paper we extend these studies and show that the SEB-induced suppressor cells also inhibit the development of cytotoxic lymphocytes in mixed-lymphocyte reaction (MLR) cultures. Since further analysis also showed that the level of interleukin 2 (IL-2) in cultures of SEB-primed cells was significantly reduced, experiments were carried out to determine the role of IL-2 in the inhibition of cytotoxic cell activity. Attempts to neutralize the suppression by supplementing MLR cocultures with delectinated supernatants from concanavalin A (Con A)-stimulated rat splenocytes were not successful. In addition, MLR cocultures supplemented on Day 0 with 50 units of affinity-purified IL-2 were also suppressed. Further analysis showed that the IL-2 activity in the supplemented MLR cocultures containing suppressor cells were significantly reduced by Day 3. However, repeated supplementation of the MLR cocultures with exogenous IL-2 was successful in achieving (and maintaining) "normal" levels of IL-2. The cytotoxic cell activity in these MLR cocultures remained suppressed. These results suggest that the inhibition of cytotoxic cell activity by SEB-induced suppressor cells is independent of IL-2 levels in the MLR coculture.

Inhibition of antibody production from the plasmacytoma cell line MOPC-315 by staphylococcal enterotoxin B-induced T-suppressor cells

Our previous results have shown that staphylococcal enterotoxin B (SEB) induces a population(s) of T cells which has the capacity to suppress the antibody response of splenocytes in vitro. In the present report we have attempted to investigate the effect of SEB-primed cells on the secretion of antibody by the plasmacytoma cell line MOPC-315. We have found that the secretion of antibody by MOPC-315 is significantly reduced in as little as 24 hr of coculture with the suppressor cells. The suppressive activity is not antigen- or isotype-specific, since the antibody secretion by both MPC-11 and HOPC1 plasmacytomas are also inhibited by the SEB-primed cells. In addition, we have found that the SEB-primed cell population which inhibits the antibody production by the MOPC-315 cell line expresses the Lyt-1+,2- and Thy-1+ cell surface markers. The apparent relationship between the SEB-primed suppressor cell population and the population which inhibits a conventional antibody response is discussed.