DNA Sequence analysis of the PorB protein of nonserotypeable serogroup C ET-15 meningococci suggests a potential mutational hot spot on their serotype antigens

The nucleotide sequences of the PorB proteins from 28 nonserotypeable serogroup C ET-15 meningococci recovered from invasive meningococcal disease cases were determined. PCR amplification of the porB genes responsible for encoding the serotype antigen was used for DNA sequence determination and identification of the nature of the serotype antigen. DNA sequencing revealed that three strains were of serotype 2a, and of the remaining 25 strains, 20 were found to have an identical single point mutation in the region of the VR3 gene, which encodes surface-exposed loop VI, where the serotype 2a epitope resides. This nonsynonymous mutation was confirmed by synthetic peptide immunochemical analysis to confer new serospecificity to these serotype 2a mutants. This finding of a potential novel mutational hot spot on the PorB proteins of meningococci may have implications for pathogenesis and vaccine development.     

Hepatitis B antigen in the liver cells in cirrhosis and hepatocellular carcinoma.

The demonstration of hepatitis B antigen in the liver cells in formalin fixed paraffin embedded tissues by Shikata's orcein staining method affords an opportunity to conduct retrospective studies on necrospy materials. Such a study in Singapore showed orcein-positive liver cells in 22 out of 52 (42.3%) and 37 out of 50 (74.0%) cases of cirrhosis of the liver and hepatocellular carcinoma respectively, while only 5 out of 113 (4.4%) 'normal' livers gave positive results. There is a significant difference in the frequency of hepatocellular carcinoma in orcein-positive and orcein-negative cirrhotic livers (28 out of 50, 10 out of 40 respectively). These results suggest a possible aetiological relationship between hepatitis B antigen and hepatocellular carcinoma.     

Peptide-based approaches to treat asthma, arthritis, other autoimmune diseases and pathologies of the central nervous system

In this review we focus on peptide- and peptidomimetic-based approaches that target autoimmune diseases and some pathologies of the central nervous system. Special attention is given to asthma, allergic rhinitis, osteoarthritis, and Alzheimer's disease, but other related pathologies are also reviewed, although to a lesser degree. Among others, drugs like Diacerhein and its active form Rhein, Pralnacasan, Anakinra (Kineret), Omalizumab, an antibody "BION-1", directed against the common beta-chain of cytokine receptors, are described below as well as attempts to target beta-amyloid peptide aggregation. Parts of the review are also dedicated to targeting of pathologic conditions in the brain and in other tissues with peptides as well as methods to deliver larger molecules through the "blood--brain barrier" by exploring receptor-mediated transport, or elsewhere in the body by using peptides as carriers through cellular membranes. In addition to highlighting current developments in the field, we also propose, for future drug targets, the components of the inflammasome protein complex, which is believed to initiate the activation of caspase- 1 dependent signaling events, as well as other pathways that signal inflammation. Thus we discuss the possibility of targeting inflammasome components for negative or positive modulation of an inflammatory response.     

Expression and characterization of recombinant soluble human CD3 molecules: presentation of antigenic epitopes defined on the native TCR-CD3 complex

The TCR-CD3 complex consists of the clonotypic disulfide-linked TCRalphabeta or TCRdeltagamma heterodimers, and the invariant CD3delta, epsilon, gamma and zeta chains. We generated plasmid constructs expressing the extracellular domains of the CD3delta, epsilon or gamma subunits fused to human IgG1 Fc. Recombinant fusion proteins consisting of individual CD3delta, epsilon or gamma subunits reacted poorly with anti-CD3 mAb including G19-4, BC3, OKT3 and 64.1. Co-expression of the CD3epsilon-Ig with either the CD3delta-Ig (CD3epsilondelta-Ig) or the CD3gamma-Ig (CD3epsilongamma-Ig) resulted in fusion proteins with much increased binding to G19-4. A brief acid treatment of the purified CD3epsilondelta-Ig fusion protein substantially improved its binding to BC3, OKT3 and 64.1. Surface plasmon resonance analysis revealed that the dissociation constants for CD3epsilondelta-Ig and anti-CD3 mAb ranged from 10(-8) to 10(-9) M. Based on these results, a single-chain (sc) construct encoding the CD3delta chain linked to the CD3epsilon chain with a flexible linker followed by human IgG1 Fc was expressed. The sc CD3deltaepsilon-scIg reacted with anti-CD3 mAb without requiring acid treatment. Moreover, anti-CD3 mAb bound CD3epsilondelta-Ig at a higher affinity than CD3epsilongamma-Ig, suggesting potential structural differences between the CD3epsilondelta and CD3epsilongamma subunits. In summary, we report the expression of soluble recombinant CD3 proteins that demonstrate structural characteristics of the native CD3 complex expressed on the T cell surface. These CD3 fusion proteins can be used to further analyze the structure of the TCR-CD3 complex, and to identify molecules that can interfere with TCR-CD3-mediated signal transduction by disrupting the interaction between CD3 and TCR subunits.     

Expression of low molecular weight cytokeratin proteins in cervical neoplasia

CAM 5.2 is a monoclonal antibody which identifies lower molecular weight cytokeratin proteins (50, 43 and 38 kD). It is an antibody which works reliably on formalin-fixed, paraffin-embedded tissues. In this study, using CAM 5.2 in the indirect immunoperoxidase method we have examined ectocervical epithelium ranging from normal, through metaplasia and cervical intraepithelial neoplasia to invasive squamous carcinoma. CAM 5.2 is demonstrated to be a useful indicator of changes associated with malignant transformation in the ectocervix.     

Activation of human T lymphocytes by crosslinking of anti-CD3 monoclonal antibodies

The proliferation of human T lymphocytes induced by anti-CD3 monoclonal antibodies (mAb) is used as a model for antigen-induced activation via the T cell receptor-CD3 complex. Since both systems are accessory cell (AC)-dependent, an understanding of the role of AC in anti-CD3-induced proliferation may provide an understanding of physiological activation via the T cell receptor. Previous work has implicated receptor crosslinking as an important AC function. To determine its necessity in anti-CD3-induced lymphocyte proliferation, we prepared highly purified T lymphocytes and found that these cells did not respond to the anti-CD3 mAb UCHT1, either alone or with interleukin 1 (IL1), interleukin 2 (IL2), or tetradecanoyl phorbol acetate (TPA). However, the response, as measured by appearance of IL2 receptors and proliferation, was restored by crosslinking with immobilized goat anti-mouse antibodies (GAM) and did not require the addition of IL1, IL2, or TPA. Thus, crosslinking of CD3 receptors was a sufficient signal for proliferation of these cells. Cyclosporine A (CsA) inhibited the activation induced by immobilized UCHT1. Since macrophages are the principle targets of CsA-mediated suppression of mitogen-induced proliferation, but macrophages do not participate in the response to immobilized anti-CD3, this may indicate that CsA was inhibiting crosslinking or a signal generated by it.