Louise McHugh

Mouse lymphocytes with and without surface immunoglobulin: preparative scale separation in polystyrene tissue culture dishes coated with specifically purified anti-immunoglobulin.

Mouse spleen cells could be preparatively separated into immunoglobulin positive (Ig+) and immunoglobulin-netative (Ig-)populations by incubating as many as 2 X 10(8) cells per 100 mm diameter petri plate coated with specifically purified goat anti-mouse immunoglobulin. The non-adherent population was 95% or more Ig-, and possessed graft versus host and cytotoxic effector activities, as would be expected for T cells. They could also give a mixed lymphocyte reaction and generate cytotoxic effector activity on culture in vitro. The adherent cells could not be released undamaged from plates coated with undiluted anti-Ig, but they could be released from plates coated with a 1/4 or 1/10 dilution of anti-Ig in an irrelevant antibody. The released cells were over 90% viable by trypan-blue staining, and 94% or more of the viable cells were Ig+.

Rational Design of Drugs That Induce Human Immunodeficiency Virus Replication

ABSTRACT Drugs that induce human immunodeficiency virus type 1 (HIV-1) replication could be used in combination with highly active antiretroviral therapy (HAART) to reduce the size of the latent reservoir that is in part responsible for viral persistence. Protein kinase C (PKC) is a logical target for such drugs because it activates HIV-1 transcription through multiple mechanisms. Here we show that HIV-1 gene expression can be induced by potent synthetic analogues of the lipid second messenger diacylglycerol (DAG) synthesized on a five-member ring platform that reduces the entropy of binding relative to that of the more flexible DAG template. By varying the alkyl side chains of these synthetic DAG lactones, it was possible to maximize their potency and ability to render latently infected T cells sensitive to killing by an anti-HIV-1 immunotoxin while minimizing the side effects of CD4 and CXCR4 downregulation and tumor necrosis factor alpha upregulation. The two lead compounds, LMC03 and LMC07, regulated a series of PKC-sensitive genes involved in T-cell activation and induced viral gene expression in peripheral blood mononuclear cells from HIV-1-infected individuals. These studies demonstrate the potential for the rational design of agents that, in conjunction with HAART and HIV-specific toxins, can be used to decrease or eliminate the pool of latently infected reservoirs by forcing viral expression.

Evidence for a factor in normal human serum that induces human neutrophilic granulocyte end-stage maturation in vitro

The end-stage maturation of neutrophilic granulocyte precursor cells isolated from normal human bone marrow by Ficoll density centrifugation was studied in a liquid culture assay system used previously to study the maturation of guinea pig granulocyte precursors. Dialyzed normal human serum induced end-stage morphological maturation of human granulocyte precursors and this induction was proportional to a serum level of up to 5.0% in the assay medium. At serum concentrations greater than 5.0% a pronounced inhibition of maturation was observed. Passage of serum through a DEAE-Fractogel 650S column equilibrated with 0.01 M phosphate buffer (pH 7.0) resulted in the binding of the end-stage granulocyte maturation factor to the column. The activity eluted from the column in a fraction containing 17% of the starting serum protein that was inhibitor-free and was also capable of inducing the appearance of granulocyte alkaline phosphatase, a specific biochemical marker for granulocyte end-stage maturation. GMF is most likely a protein since it was destroyed by protease digestion. The data also indicate that neither purified human transferrin nor human recombinant granulocyte colony-stimulating factor can substitute for human serum GMF as a granulocyte end-stage maturation factor in this assay system. It was observed, however, that purified human transferrin greatly potentiated the effect of GMF suggesting that transferrin plays a supporting role in the end-stage maturation of human granulocytes in vitro. To our knowledge the evidence presented here indicates for the first time the existence of a neutrophilic granulocyte end-stage maturation factor in normal human serum.

Polyacrylamide-streptavidin: a novel reagent for simplified construction of soluble multivalent macromolecular conjugates

We have developed a soluble macromolecular conjugation reagent, polyacrylamide-streptavidin (PASA), for the simplified preparation of multivalent protein-protein conjugates. Soluble linear polyacrylamide, with a molecular weight of approximately 10(6), has carboxyl groups generated by limited alkaline hydrolysis. It is then activated with carbodiimide, separated from excess carbodiimide, and conjugated to streptavidin. The resulting conjugate, which has approximately 20 streptavidin residues per molecule, can bind biotinylated proteins to produce homo- or heteroconjugates of known composition. We have used this technique to prepare soluble multivalent heteroligating antibody conjugates that can bind either of two antigenically distinct cell lines, as well as reagents that specifically label murine tumor cells with different MHC class I antigens. The method is potentially useful for making multivalent arrays of epitopes for measuring low affinity interactions such as that between the T cell receptor and MHC molecules, as well as for making immunotoxins, tumor labelling conjugates, and complex immunogens.

Live microbial microbicides for HIV

Background Most HIV transmission occurs on the mucosal surfaces of the gastrointestinal and cervico-vaginal tracts, which are coated by a biofilm of commensal bacteria. We are genetically engineering such naturally occurring bacteria to secrete peptides that block viral infection or replication. Introduction of such genetically modified organisms into uninfected individuals under conditions where they colonize the mucosa would provide a long lasting bioshield against HIV.