Sulnn'lary Tumor necrosis factor ot (TNF-ot) is a pleiotropic cytokine triggering cell responses through two distinct membrane receptors. Stimulation of leukocyte adhesion to the endothelium is one of the many TNF-ot activities and is explained by the upregulation of adhesion molecules on the endothelial cell surface. Human umbilical vein endothelial cells (HUVEC) were isolated, cultured, and demonstrated to express both TNF receptor types, TNF-K55 and TNF-R75. Cell adhesion to HUVEC was studied using the HL60, U937, and MOLT-4 cell lines. HUVEC were activated by either TNF-ot, binding to both TNF-R55 and TNF-K75, and by receptor type-specific agonists, binding exclusively to TNF-R55 or to TNF-K75. The TNF-ot-induced cell adhesion to HUVEC was found to be controlled almost exclusively by TNF-R55. This finding correlated with the exclusive activity of TNF-K55 in the TNF-ot-dependent regulation of the expression of the intercellular adhesion molecule type 1 (ICAM-1), E-selectin, and vascular cell adhesion molecule type 1 (VCAM-1). The CD44 adhesion molecule in HUVEC was also found to be upregulated through TNF-K55. However, both TNF-R55 and TNF-R75 upregulate ot2 integrin expression in HUVEC. The predominant role of TNF-R55 in TNF-ot-induced adhesion in HUVEC may correlate with its specific control of NF-xB activation, since xB elements are known to be present in ICAM-1, E-selectin, and VCAM-1 gene regulatory sequences.

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A system is described which permits the efficient synthesis of single proteins in vitro. The essential element in this expression system is a strong promoter derived from coliphage T5 which produces, with high efficiency, specific RNAs in capped or uncapped form, depending upon the experimental conditions used. The transcription‐coupled capping of RNA allows the direct translation of the RNA in eukaryotic extracts from wheat germ as well as from HeLa cells. The synthesis of three different proteins is reported, including lysozyme, which is shown to be translocated across membranes when appropriate assay conditions are used. The simplicity of the experimental procedure, the high purity and specific activity of the [35S]methionine‐labelled proteins produced offer a number of possibilities for the study of structure‐function relationships of proteins.

The copy number of plasmids containing the ColE1 replicon is affected by changes in the transcriptional activity within the plasmid if these changes lead to transcriptional readthrough into the replication region towards the promoter priming DNA replication. Such readthrough e.g., from the tet region in pBR322 not only causes overproduction of a peptide known to affect the copy number negatively but also appears to interfere negatively with the replication of the plasmid itself. The proper placement of efficient transcriptional terminators prevents such interference and permits the stable integration of strong promoters. Due to this termination effect, up to 9‐fold differences in plasmid copy number were observed, depending upon the particular growth conditions. The higher copy number is of course reflected by higher yields of plasmid‐specified gene products indicating the relevance of the above effects for studies of gene expression.

To circumvent problems associated with polymorphic vaccine candidates for Plasmodium falciparum malaria, we evaluated recombinant proteins representing sequences from relatively highly conserved regions of the precursor to the major merozoite surface proteins, gp190, for their ability to protect Saimiri monkeys against malaria challenge. Recombinant proteins represented amino acid residues 147 to 321 (p190-1) or 147 to 321 and 1060 to 1195 (p190-3), and their efficacy was compared with that of native gpl90 and its processed products. All antigens were derived from P. falciparum Ki, a Thai isolate, while the challenge strain was Palo Alto (from Uganda, Africa), which contains, with the exception of the N-terminal 375 amino acids, which are almost identical to the Kl sequence, essentially the MAD-20 allelic form of gpl90. By 12 days following challenge, each control monkey required drug treatment. Three monkeys injected with p190-3 required therapy, while one cleared the parasites without therapy. Two monkeys injected with p190-1 received therapy on day 14, while the remaining two cleared the parasites without therapy. Of four animals injected with native gpl90, because of health reasons unrelated to malaria, one was not challenged with parasites and one was removed from the study 8 days after challenge when its parasitemia was 1.1% (parasitemias in control animals ranged from 4.3 to 9%); the remaining two cleared the parasites after maximum parasitemias of 0.45 and 0.53%. The highest levels of antiparasite antibody were produced by animals immunized with native gpl90. There was a significant correlation between monkeys which did not require drug treatment and antiparasite antibody. These results may suggest that native gpl90 and/or its processed products can provide excellent protection against heterologous challenge and that antibody is important for protection. The challenge for vaccine development is to identify the protective sequence(s).