Molecular preservation in Late Cretaceous sauropod dinosaur eggshells.

Exceptionally preserved sauropod eggshells discovered in Upper Cretaceous (Campanian) deposits in Patagonia, Argentina, contain skeletal remains and soft tissues of embryonic Titanosaurid dinosaurs. To preserve these labile embryonic remains, the rate of mineral precipitation must have superseded post-mortem degradative processes, resulting in virtually instantaneous mineralization of soft tissues. If so, mineralization may also have been rapid enough to retain fragments of original biomolecules in these specimens. To investigate preservation of biomolecular compounds in these well-preserved sauropod dinosaur eggshells, we applied multiple analytical techniques. Results demonstrate organic compounds and antigenic structures similar to those found in extant eggshells.

Initial studies of the molecular basis of peptide mimicry of group B streptococcal type III capsular polysaccharide.

We have previously shown that the peptide FDTGAFDPDWPA is a mimetic of the group B streptococcal type III capsular polysaccharide (CPS(III)). It binds to anti-CPS(III) antibodies and can be used to immunize mice and produce anti-CPS(III). In this paper we investigate the molecular mechanisms underlying this peptide-carbohydrate mimicry in two ways. First, we have examined the conformation of the peptide by NMR spectroscopy in water. Next, we have produced monoclonal anti-peptide and anti-CPS(III) antibodies, compared their fine specificity, and have sequenced them. The results indicate that the peptide assumes a conformation that may be similar to that of the CPS(III) in solution and that the peptide and CPS(III) elicit an overlapping repertoire of antibodies.

11 Targeting HIV-Infected Cells.

This chapter will describe methods that may be used to deliver agents to HIV-infected cells. These materials may be used for therapeutic or experimental purposes. There are several general approaches to delivering compounds to human immunodeficiency cells (HIV)-infected cells. All cells may be exposed to materials that only have an effect or become activated in HIV-infected cells. Examples include drugs that are specific for HIV-encoded enzymes, such as reverse transcriptase or protease, or genes that are expressed under the control of the HIV-LTR. Lack of specificity is a major limitation to this approach; for example, reverse transcriptase inhibitors also inhibit cellular DNA polymerases and cellular transcription factors clan initiate low-level-transcription off the HIV-LTR, even in the absence of tat. The alternative approach, which is the subject of this chapter, is to target the materials specifically to the infected cells. We have used monoclonal antibodies (MAbs) to deliver toxins to HIV-infected cells, but others have used this approach to deliver antiviral agents, liposomes, and even genes.

Peptide ligands that bind IgM antibodies and block interaction with antigen.

We have selected a peptide-display phage library on IgM Abs and identified a panel of phage-expressing peptides that bind to IgM Abs in general, but not to Abs of other classes. A synthetic peptide corresponding to one of the displayed peptide sequences also binds to IgM Abs. The peptides bind to both soluble pentameric Abs and to monomeric cell-surface IgM. The phage-displayed and synthetic peptides inhibit the binding of IgM Abs to Ag. These peptides may create confounding artifacts when IgM Abs are used for epitope mapping studies. Nonetheless, the peptides may have both experimental and therapeutic utility.

Tazarotene 0.1% gel plus corticosteroid cream in the treatment of plaque psoriasis.

BACKGROUND: Topical corticosteroids are often used in the treatment of psoriasis, but long-term use may be associated with serious adverse events such as tachyphylaxis or atrophy of the skin. Tazarotene, a new topical retinoid, has demonstrated significant clinical benefits but can cause mild to moderate local irritation. OBJECTIVE: We evaluate whether a combination treatment of topical tazarotene and a topical corticosteroid would increase efficacy while reducing the incidence of local adverse events associated with a topical retinoid. METHODS: Three hundred patients enrolled in an investigator-masked study were randomly assigned to 1 of 4 treatment groups: tazarotene 0.1% gel in combination with placebo cream, or with a low-, mid-, or high-potency corticosteroid cream, for 12 weeks of treatment and a posttreatment follow-up at week 16. RESULTS: Tazarotene 0.1% gel in combination with a mid- or high-potency corticosteroid, when compared with tazarotene plus placebo cream, achieved significantly greater reductions in scaling, erythema, and overall lesional severity, and a decreased incidence of adverse events. CONCLUSION: All tazarotene combinations (including tazarotene plus placebo) were highly effective in rapidly reducing the severity of psoriasis. Combining tazarotene with a topical corticosteroid increased efficacy while reducing the incidence of local adverse events.

Efficacy and safety of azelaic acid and glycolic acid combination therapy compared with tretinoin therapy for acne.

We conducted a 12-week, multicenter, randomized, double-masked, parallel-group study of the efficacy, safety, and tolerability of azelaic acid 20% cream and glycolic acid lotion compared with tretinoin 0.025% cream and a vehicle lotion to treat mild-to-moderate facial acne vulgaris. Patients treated with azelaic/glycolic acid experienced a significantly greater reduction in the number of papules, as well as a greater reduction in the number of inflammatory lesions, than those treated with tretinoin. Overall global improvement was approximately 25% in both groups. In the physician evaluations, treatment with azelaic/glycolic acid was found to cause significantly less dryness, scaling, and erythema than tretinoin. Patients also reported significantly less dryness, redness, and peeling with azelaic/glycolic acid. Significantly more patients in the azelaic/glycolic acid group than the tretinoin group reported that they felt attractive. The combination of azelaic acid and glycolic acid is a useful alternative to tretinoin, being at least as efficacious as the latter, while offering a superior tolerability and patient approval profile.

Operational stress control in the former Yugoslavia: a joint endeavor.

The military has developed specialized mental health teams to evaluate and treat soldiers diagnosed with stress reactions and neuropsychiatric disorders. The response of these mental health teams in support of the year-long peace enforcement mission to Bosnia-Herzegovina is reviewed. Demographics and operational stressors are examined. Stress control doctrine is tested and revised. Credibility with leaders, chaplains, and medical personnel is achieved through rapid response to serious injury or fatality. Emphasis is placed on successful marketing strategies, stress management and suicide prevention classes, prompt access to care, and decreasing the stigma of mental health through education. Coordination of mental health assets promotes synergy and mission accomplishment.

Immunologic cross-reaction between HIV type 1 p17 and Mycoplasma hyorhinis variable lipoprotein.

Monoclonal antibodies directed against the HIV-1 matrix protein p17 that react with a component present on the surface of HIV-1-infected cells have previously been described. In this study we show that one of these monoclonal antibodies binds to persistently HIV-1-infected cell lines that are coinfected with Mycoplasma hyorhinis, but not to cell lines that are uninfected with mycoplasma. Mycoplasma-infected cells secrete HIV-1 at a higher rate, have a slight increase in cell surface expression of gp120 and gp41, and are less sensitive to immunotoxins than uninfected cells. The anti-p17 antibody binds to a protein of M. hyorhinis grown in cell-free culture. The variable expression and size of the protein among strains is typical of the variable lipoprotein (Vlp) system of M. hyorhinis. Confirmation of the reactivity of the antibody with a Vlp was provided by demonstrating its specific binding to recombinant VlpF expressed in E. coli, and to a synthetic peptide representing the carboxy-terminal region of VlpF, but not to other recombinant Vlp products or peptides. This is a true cross-reaction because the antibody also binds to recombinant p17 expressed in E. coli and the binding is inhibited by the VlpF peptide. These analyses highlight the potential of mycoplasma contamination of tissue culture cell lines to cause anomalous results. With regard to HIV-1, mycoplasma infection of cells results in increased rates of virus secretion, and introduces a potential confounding immunologic cross-reaction as well. The existence of a cell surface form of p17 is unlikely.

Peptides that mimic the group B streptococcal type III capsular polysaccharide antigen.

Microbial polysaccharides are notably poor immunogens. We have developed an alternate route for the production of Abs to important carbohydrate epitopes. mAb S9, a protective mAb against the type III capsular polysaccharide of group B streptococci (GBS), was used to select epitope analogues from a peptide display phage library. Depending upon desorption conditions, two populations of phage were identified with displayed sequences of WENWMMGNA and FDTGAFDPDWPA. ELISA results demonstrated that these phage bound to S9 and no other Abs. Phage blocked the binding of S9 to type III GBS, but did not block binding by another anti-GBS mAb. Phage displaying the latter peptide sequence showed greater inhibition. Ab S9 and other monoclonal and polyclonal anti-GBS type III antisera bound the synthetic peptide FDTGAFDPDWPAC. The binding of S9 to GBS was inhibited by the free peptide with an IC50 of 30 microg/ml. The binding of polyclonal anti-GBS antibodies to peptide could be blocked by intact GBS as well as purified capsular polysaccharide. The peptide was conjugated to three different carriers and was used to immunize mice. All mice produced a significant antibody response to GBS and to the purified capsular polysaccharide following a single immunization. These data demonstrate that a peptide mimetic of the GBS capsular polysaccharide is both antigenic and immunogenic. The incorporation of such peptides into vaccine preparations may enhance the efficacy of vaccines in inducing Ab responses to important carbohydrate epitopes.

Vaccine-specific antibody responses induced by HIV-1 envelope subunit vaccines.

The first generation of candidate vaccines to prevent HIV infection consisted of recombinant envelope proteins (Env, gp120, and gp160) derived from a single laboratory strain of HIV, designated IIIB/LAV, but produced with different expression systems. In this study we examined the fine specificity of the human Ab response to each vaccine and compared them to the responses of laboratory workers infected with the same strain of HIV. The best responders from each vaccine protocol were studied and compared. Detailed comparisons of the fine specificity of the Ab response were possible because all immunologic assays were performed using homologous recombinant proteins, peptides, and virus stocks. Although the total amounts of anti-Env Ab were comparable, the groups exhibited significant differences in epitope specificity, avidity, and functional capacity of the Ab response. The data demonstrate that the form of the immunogen (e.g., live virus or recombinant protein) is important in determining the quality of the Ab response. Conclusions are also drawn regarding characteristics of the anti-HIV-neutralizing Ab response. These studies represent one of the most detailed analyses of the human Ab response to any Ag and have implications for the development of vaccines for HIV as well as for other microbial pathogens.

Influence of endosome-destabilizing peptides on efficacy of anti-HIV immunotoxins.

The effects on immunotoxin efficacy of fusogenic peptides derived from influenza virus hemagglutinin have been studied. These peptides have an amphipathic nature and change conformation from random at pH 7 to helical at pH 5. Fusogenic peptides are reported to destabilize endosomal membranes, resulting in the release of contents into the cytoplasm. The use of two related fusogenic peptides to enhance the efficacy of anti-HIV immunotoxins is described. The direct toxicity of the peptides was tested on HIV-infected H9/NL4-3 cells. Peptide HA24 was considerably more toxic than HA23. The peptides were mixed with two different immunotoxins. Immunotoxin action was enhanced by both peptides, with HA24 providing greater enhancement than HA23. Immunotoxins were then constructed by coupling HA23 or HA24 to the targeting antibody with disulfide-containing linkers. Peptide HA23 enhanced the activity of the immunotoxin 4-5-fold. Surprisingly, HA24 significantly inhibited immunotoxin activity. Coupling the peptides to the immunotoxin had no effect on antigen binding characteristics or the activity of the toxic moiety. Bafilomycin A1, an agent that inhibits vacuolar acidification, markedly potentiated the effects of all immunotoxins. These results demonstrate that amphipathic peptides can influence the efficacy of immunotoxins, but in sometimes unpredictable ways.

Therapeutic potential of anti-HIV immunotoxins.

In vitro analyses have shown anti-HIV immunotoxins to be among the most effective AIDS antivirals tested. Because HIV has been continually selected by antibody, immunotoxins targeted to constant domains of viral antigens may not elicit drug-resistant mutants. A clinical trial with CD4-PE40, a possibly flawed immunotoxin with nonspecific toxicity and short serum half-life, has reduced interest in this form of therapy. It is proposed that the use of an immunotoxin directed against gp41 in combination with a CD4-Ig chimera is more likely to have a therapeutic effect than CD4-PE40. Clinical trials are also underway utilizing an immunotoxin that eliminates activated T-cells, an important cellular locus of HIV-replication.

In vitro effects of anti-HIV immunotoxins directed against multiple epitopes on HIV type 1 envelope glycoprotein 160.

We have used a panel of anti-gp160 MAbs to construct anti-HIV immunotoxins by coupling antibodies to ricin A chain (RAC). The ability of the immunotoxins to kill HIV-1-infected cells and halt the spread of infection was tested in tissue culture on persistently and acutely infected cell lines and primary lymphocyte cultures stimulated with phytohemagglutinin (PHA blasts). Laboratory strains and clinical isolates of HIV both were tested. The constitution and antigen-binding capacity of the immunotoxins were confirmed by ELISA and indirect immunofluorescence. Immunotoxins that bind epitopes exposed on the cell surface effectively killed persistently infected cells, although killing was not directly proportional to binding of immunotoxin to cell. The activity of anti-gp41, but not anti-gp120, immunotoxins was markedly enhanced in the presence of soluble CD4 or peptides corresponding to the CDR3 region of CD4. CD4-mediated enhancement of anti-gp41 immunotoxin activity was observed for laboratory strains neutralized by sCD4 and for clinical isolates that were resistant to neutralization by sCD4. Immunotoxin action was potentiated by brefeldin A, bafilomycin A1, cortisone, and an amphipathic fusion peptide, but not by cytochalasin D, nocodazol, monodansyl cadaverine, or trans-retinoic acid. Anti-HIV immunotoxins are useful tool with which to study the functional expression of gp120/gp41 antigens on the surface of HIV-infected cells, as well as potential AIDS therapeutics. Because these studies relate to the accessibility of viral antigens to antibody-mediated attack, these studies also have relevance for vaccine development.

Topical calcipotriene has no short-term effect on calcium and bone metabolism of patients with psoriasis.

BACKGROUND: The biologically active form of vitamin D3, calcitriol, is effective in the treatment of psoriasis but can alter calcium metabolism. Calcipotriene is an analog of calcitriol that has low calcemic activity and aids in clearing psoriasis. OBJECTIVE: The purpose of this study was to determine the safety of topical therapy with calcipotriene particularly in relation to calcium and bone metabolism. METHODS: In a double-blind, randomized, parallel, vehicle-controlled trial, 78 adults with plaque psoriasis were treated twice daily with topical calcipotriene ointment (50 microgram/gm, maximum usage, 120 gm per week) or vehicle for 8 weeks. After a screening visit, patients were admitted to the hospital at weeks 0 (baseline), 1,2,4, and 8. Blood and urine chemistry analysis included parathyroid hormone, serum calcium, bone-specific alkaline phosphatase, urinary hydroxyproline, and 24 hour urinary calcium excretion. Bone densitometry measures were performed at baseline and week 8. RESULTS: No incidences of calcipotriene treatment-related hypercalcemia, calcium mobilization from bone, or clinically significant changes in bone density wer noted during this study. CONCLUSION: Topical application of up to 120 gm per week of calcipotriene ointment for 8 weeks is safe and effective for plaque psoriasis. There were no adverse effects on calcium and bone metabolism during this 8 week study.

Processing of the envelope glycoprotein gp160 in immunotoxin-resistant cell lines chronically infected with human immunodeficiency virus type 1.

We describe the isolation and characterization of variant cell lines which are chronically infected with the human immunodeficiency virus (HIV) and resistant to the action of immunotoxins directed against the HIV envelope protein. These variants all produce normal levels of HIV proteins, budding virions, and the envelope protein precursor gp160. Two of the variants, 10E and 11E, contain a mutation within the env gene which results in the production of a truncated precursor and altered processing and transport of the protein to the cell surface. Variants B9 and G4 are defective in gp160 cleavage and do not efficiently transport the envelope protein to the cell surface. There are no mutations in the expressed viruses of B9 and G4. These cell lines express higher levels of CD4 protein and mRNA than H9/NL4-3. Thus, 10E, 11E, B9, and G4 have escaped immunotoxin action by downmodulating the envelope protein from their cell surfaces. None of these variants produce infectious HIV. Two other immunotoxin-resistant variants, E9-3 and 41-17, produce normal levels of gp160, efficiently transport the cleaved and processed subunits to the cell surface, and secrete infectious HIV. These studies identify alterations in gp160 processing that underscore the importance of the relationship between HIV and the cell that it infects.

Protective efficacy of nonneutralizing monoclonal antibodies in acute infection with murine leukemia virus.

We have used an experimental retrovirus infection to study the roles played by different antibodies in resistance to both infection and disease. A molecularly cloned chimeric murine leukemia virus was used to induce acute lethal neurological disease in neonatal mice. A panel of monoclonal antibodies directed against the Gag and Env proteins was tested for protective efficacy. In vitro neutralization assays demonstrated that anti-Env antibodies gave different degrees of neutralization, while no anti-Gag neutralized the virus. In vivo experimental endpoints were onset of clinical signs and premoribund condition. As expected, different anti-Env antibodies demonstrated different degrees of protection which correlated with their neutralizing abilities. Surprisingly, anti-Gag antibodies directed against both p15 (MA protein) and p30 (CA protein) were also protective, significantly delaying the onset of disease. No protection was seen with either of two control antibodies. The protection with anti-Gag was dose related and time dependent and was also produced with Fab fragments. Treatment with anti-Gag did not prevent viremia but resulted in a slight slowing in viremia kinetics and decreased levels of virus in the central nervous systems of mice protected from disease. These data indicate that nonneutralizing antiretroviral antibodies can influence the outcome of retroviral disease. The data also suggest a functional role for cell surface expression of Gag proteins on murine leukemia virus-infected cells.