Attenuation of inflammation and cytokine production in rat colitis by a novel selective inhibitor of leukotriene A4 hydrolase.

BACKGROUND AND PURPOSE: Leukotriene B(4) (LTB(4)), formed by the sequential actions of the 5-lipoxygenase (5-LO) and leukotriene A(4) hydrolase (LTA(4)H), is a pro-inflammatory mediator implicated in the pathogenesis of inflammatory bowel disease. However, inhibitors of 5-LO have not proved to be consistent in their therapeutic efficacy in colitis. Another approach to inhibiting LTB(4) synthesis is through the use of inhibitors of LTA(4)H, such as the novel, potent and selective compound, JNJ 26993135. EXPERIMENTAL APPROACH: The effect of oral administration of JNJ 26993135 has been evaluated in a rat model of colitis provoked by colonic instillation of trinitrobenzenesulphonic acid (TNBS). The extent and severity of the macroscopic inflammatory response, the colonic levels of myeloperoxidase (MPO) and LTB(4) and of the pro-inflammatory cytokines, tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) were measured. KEY RESULTS: Oral administration of JNJ 26993135 (5, 15 and 30 mg kg(-1), twice a day) dose-dependently reduced both the extent and intensity of the colonic inflammatory damage observed 3 days after TNBS challenge. JNJ 26993135 also dose-dependently reduced the elevated colonic levels of LTB(4), as well as the inflammatory biomarkers, MPO, IL-6 and TNF-alpha. This dosing regimen was supported by the pharmacokinetic profile of JNJ 26993135, along with the demonstration of the inhibition of ex vivo production of LTB(4) in whole blood following oral administration. CONCLUSIONS AND IMPLICATIONS: These results with JNJ 26993135 in the rat TNBS model support the role of LTB(4) in colitis and the potential value of targeting LTA(4)H for the treatment of inflammatory bowel diseases.

Identification of a new shared HLA-A2.1 restricted epitope from the melanoma antigen tyrosinase.

Tyrosinase has many advantages as a target antigen for the immunotherapy of patients with melanoma because it is expressed in nearly all melanoma specimens with a high degree of cellular homogeneity, and its distribution in normal tissues is limited to melanocytes. To broaden our ability to direct cellular immune responses against this protein, we pursued an investigation to identify new shared human leukocyte antigen (HLA)-A2.1 restricted epitopes from tyrosinase. Peptides were synthesized that fit a permissive HLA-A2.1 binding motif and did not span common sites of polymorphism. The binding affinity of each peptide to HLA-A2.1 relative to a standard peptide with intermediate binding affinity was evaluated in a competitive inhibition assay. Twelve peptides were selected that had binding affinities within 80% of that of the standard peptide, and these were used to stimulate peripheral blood mononuclear cells (PBMC) in vitro from three HLA-A2.1+ patients with metastatic melanoma. Cytotoxic T lymphocytes that specifically recognized peptide-pulsed target cells as well as HLA-A2.1+ tyrosinase+ melanoma cells were raised from one patient with tyrosinase:8-17 (CLLWSFQTSA). To evaluate further the immunogenicity of this peptide, PBMC from 23 HLA-A2.1+ patients were stimulated in vitro with tyrosinase:8-17. Eleven bulk T-cell cultures demonstrated specific peptide recognition, and six of these also recognized HLA-A2.1+ tyrosinase+ melanoma cells. These data suggest that tyrosinase:8-17 may be clinically useful for the treatment of patients with melanoma.

Relative reactivity of the V3 loop PND of HIV-1 subtypes A, B, C, D, and F with sera from selected Ugandan localities.

Synthetic peptides comprising the predicted principal neutralizing determinant (PND) in new African and North American HIV-1 clones were tested in ELISA for reactivity with ninety six serum samples from asymptomatic donors in six selected localities in Uganda. Irrespective of the geographical origin of the samples, the majority of the test sera cross-reacted at high intensities with the peptides derived from the North American clone, BRT3.6 (Group B), the Ugandan clone, CUG045, (Group C), and the Romanian clone, FRMA (Group F). The frequency of reactivity of the peptides from BRT3.6, CUG045, and FRMA were within the ranges of 57-100%, 50-100%, and 57-100%, respectively, for the sera collected from these disparate localities. In contrast to these findings, the V3 peptides derived from the other Ugandan isolates showed a more restricted pattern of reactivity with the same serum samples: AUG06c (1-63%), DUG23c (2%), and DUG044 (38-87%). The results from ELISA inhibition assay indicated that the V3 peptide from BRT 3.6, CUG045, and FRMA express closely related antigenic specificities quite distinct from those in AUG06c and DUG044. The residues comprising the PND in BRT 3.6, CUG045, and FRMA appear to be well conserved in the HIV-1 subtypes prevalent in the selected Ugandan locales.

PIP: In Uganda, health workers collected serum samples from 96 asymptomatic HIV-1 infected blood donors in Ishaka and Mbarara (southwest), Kisenyi and Kampala (central), and Lugazi and Jinja (east) so researchers working in a biochemistry laboratory at The City University of New York could describe the relative reactivity of the V3 loop from HIV-1 subtypes A, B, C, D, and F, as well as study the antigenic relationships within the PND encoded in the divergent HIV-1 subtypes. Regardless of geographic origin, the V3 peptides from most of the sera (at least 50%) collected in Uganda cross-reacted at high frequencies with the peptides derived from the novel North American clone (BRT3.6), the Ugandan clone (CUG045), and the Romanian clone (FRMA). The frequency of reactivity of these peptides with the test sera ranged from 57% to 100% for BRT3.6, from 50% to 100% for CUG045, and from 57% to 100% for FRMA. The V3 peptides from other Ugandan isolates (AUG06c, DUG044, and DUG23c) were less reactive with the same serum samples than BRT3.6, CUG045, and FRMA: 1-63%, 38-87%, and 2%, respectively. This finding suggests that the antigenic determinants expressed in AUG06c, DUG044, and DUG23c may not represent the PND encoded in most HIV-1 strains afflicting the Ugandan communities. The V3 peptides from BRT3.6, CUG045, and FRMA express closely related antigenic specificities altogether different from those in AUG06c and DUG044. The HIV-1 subtypes present in the selected Ugandan sites appear to effectively conserve the residues making up the PND in BRT3.6, CUG045, and FRMA.

Distribution of linear antigenic epitopes on GP120 encoded in sibling clones of novel New York HIV-1 subtype B isolates.

We have initiated studies to characterize the predominant subtypes of HIV-1 which account for infections in a defined cohort of intravenous (IV) drug addicts. A region of ENV encoding the C2 to the V5 regions was amplified from the leukocytes of two subjects currently enrolled in a methadone maintenance program at the Addiction Research and Treatment Corporation (ARTC), in Brooklyn, New York. This region of the viral genome encodes the principal neutralizing determinant (PND) located in the V3 loop, the immunogenic CD4-binding site, and six other linear antigenic epitopes in the envelope glycoprotein, gp120. Phylogenetic tree analysis of the nucleotide sequences showed that the sibling clones RT1.4, RT1.15, RT1.17, RT1.21 and RT3.6, RT3.10, RT3.11, RT3.12 and RT3.15 derived from the isolates, RT1 and RT3, respectively, cluster with "group B" viruses at 99% confidence level. Marked intra-patient and inter-patient sequence variation was apparent in the V3 loop. The divergence included the presence of a previously unreported hexapeptide GPWGTF at the cap of the loop in the clones from RT1. The North American consensus hexapeptide, GPGRAF, was identified in the cap of the loop from the clones of RT3. Four of the five sibling clones from RT3 were closely related whereas the other clone, RT3.15, displayed five amino acid mutations downstream of the V3 cap. To assess the effect of sequence variation on the distribution of linear antigenic epitopes, complementary computer software programs, were used to analyze the gp120 residues. Eight analogous antigenic epitopes were identified in the clones from both isolates despite the marked divergence in the primary sequences.(ABSTRACT TRUNCATED AT 250 WORDS)

Management of central nervous system infections during an epidemic of enteroviral aseptic meningitis.

Four hundred and fifty-six patients with signs and symptoms of potential central nervous system infection were evaluated from June 28, 1978, to September 30, 1978. The majority of the children had a relatively brief and mild illness characterized by a constellation of features previously described with central nervous system infections. Fever, headache, and vomiting were typical. Altered sensorium and nuchal rigidity were inconstant. One distinct and another infrequently reported feature of enteroviral disease, hypoglycorrhachia and cerebrospinal fluid pleocytosis in excess of 2,000 cells/mm3, occurred independently or in concert in 18% of the cases. When these unexpected findings were associated with a presumptive clinical diagnosis of aseptic meningitis, watchful observation and repeat lumbar puncture precluded the necessity to administer antibiotics in every case. The possibility of enteroviral aseptic meningitis being a definitive diagnostic entity manageable on a group, yet individual basis utilizing a disposition protocol is discussed.