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Identification of physiologically relevant peptide vaccine targets calls for the direct analysis of the entirety of naturally presented human leukocyte antigen (HLA) ligands, termed the HLA ligandome. In this study, we implemented this direct approach using immunoprecipitation and mass spectrometry to define acute myeloid leukemia (AML)-associated peptide vaccine targets. Mapping the HLA class I ligandomes of 15 AML patients and 35 healthy controls, more than 25 000 different naturally presented HLA ligands were identified. Target prioritization based on AML exclusivity and high presentation frequency in the AML cohort identified a panel of 132 LiTAAs (ligandome-derived tumor-associated antigens), and 341 corresponding HLA ligands (LiTAPs (ligandome-derived tumor-associated peptides)) represented subset independently in >20% of AML patients. Functional characterization of LiTAPs by interferon-γ ELISPOT (Enzyme-Linked ImmunoSpot) and intracellular cytokine staining confirmed AML-specific CD8+ T-cell recognition. Of note, our platform identified HLA ligands representing several established AML-associated antigens (e.g. NPM1, MAGED1, PRTN3, MPO, WT1), but found 80% of them to be also represented in healthy control samples. Mapping of HLA class II ligandomes provided additional CD4+ T-cell epitopes and potentially synergistic embedded HLA ligands, allowing for complementation of a multipeptide vaccine for the immunotherapy of AML. [ABSTRACT FROM AUTHOR]

The Leu-8/TQ1 antigen, recently shown to be the human equivalent of the murine MEL-14 lymph node homing receptor and now designated as leucocyte-endothelial cell adhesion molecule, LECAM-l, has been used to dissect T, B and natural killer (NK) cells into various subpopulations with different functional properties, such as suppressor-inducer (CE4+ Leu-8/TQ1+) or helper (CD4+ Leu-8/TQ1-) T lymphocytes. Diminished Leu-8/TQ1 antigen density has been reported after lymphocyte activation with B- or T-cell specific stimuli for several days. In the present study, we sought to determine the signal requirements for altered Leu-8/TrQ1 expression. Exposure of freshly isolated peripheral blood lymphocytes to phorbol 12-myristate 13-acetate (PMA) and/or calcium ionophores was found to cause rapid down-regulation of the Leu-8 antigen, with little or no Leu-8 reactivity remaining I hr after simultaneous addition of PMA and calcium ionophores to the culture medium. TQ1 reactivity was changed in parallel with that of Leu-8. Leu-8 expression oft and B cells was sensitive to both PMA and calcium ionophores, whereas Leu-8 expression of NK cells was affected by PMA but not by the calcium ionophore A23187. The effect of PMA on Leu-8/TQ1 expression could be antagonized by pretreatment with the protein kinase C inhibitor, H7, whereas that of A23187 could not. Partial re-expression of the Leu-8 antigen was seen 3 days after addition of PMA alone but not when it was given together with calcium ionophores. After Leu-8 down regulation induced by I hr treatment with PMA or calcium ionophores, Leu-8 re-expression was observed within 24 hr when stimuli were removed by washing. Activation oft cells with anti-CD3 antibody resulted in a partial reduction of Leu-8/TQ1 expression, first detectable after 1-3 hr of stimulation and maximal at 24 hr. Fully mitogenmic concentrations of concanavalin A (Con A) did not affect Leu-8 expression within the first hours of culture. Transient reduction of Leu-8 expression was seen 24 hr after supraoptimal dosages of Con A, but Con A-stimulated lymphocytes cultured for 4-12 days with interleukin-2 (IL-2) retained Leu-8/TQ1 reactivity to a similar degree as fresh cells. In contrast to Leu-8/TQ1, CD45RA expression was not altered after I hr treatment with PMA and/or calcium ionophores but gradually disappeared during I week after Con A stimulation. Thus, Leu-8/ TQ1+ CD45RA+ lymphocytes could be rapidly converted into Leu-8/TQ1 CD45RA+ cells by PMA and/or calcium ionophores in vitro within 1 hr, whereas Leu-8/TQ1+ CD45RA- cells were generated by Con A stimulation over several days. [ABSTRACT FROM AUTHOR]

Explores the ability of alpha4 integrins, especially alpha4beta7, to mediate selectin-independent interaction and rolling of lymphocytes under physiologic flow in vitro and in vivo. Alpha4beta7 support for activation-enhanced sticking and mediation of L-selectin (CD62L)-independent attachment of blood-borne lymphocytes to lamina propria venules in situ; Presentation on microvilli.

Reports on the mucosal vascular addressin MAdCAM-1, a mucosal endothelial adhesion molecule with immunoglobulin- and mucin-like venule (HEV) ligands for the lymphocyte L-selectin homing receptor; Interacting lymphoid cells' display of a `rolling' behavior similar to selectin-dependent rolling of neutrophils observed in inflamed venules.

Background: Mutations in the GJB2 gene cause one form of nonsyndromic recessive deafness. Among Mediterranean Europeans, more than 80 percent of cases of nonsyndromic recessive deafness result from inheritance of the 30delG mutant allele of GJB2. We assessed the contribution of mutations in GJB2 to the prevalence of the condition among Ashkenazi Jews.Methods: We tested for mutations in GJB2 in DNA samples from three Ashkenazi Jewish families with nonsyndromic recessive deafness, from Ashkenazi Jewish persons seeking carrier testing for other conditions, and from members of other ethnic groups. The hearing of persons who were heterozygous for mutations in GJB2 was assessed by means of pure-tone audiometry, measurement of middle-ear immittance, and recording of otoacoustic emissions.Results: Two frame-shift mutations in GJB2, 167delT and 30delG, were observed in the families with nonsyndromic recessive deafness. In the Ashkenazi Jewish population the prevalence of heterozygosity for 167delT, which is rare in the general population, was 4.03 percent (95 percent confidence interval, 2.5 to 6.0 percent), and for 30delG the prevalence was 0.73 percent (95 percent confidence interval, 0.2 to 1.8 percent). Genetic-linkage analysis showed conservation of the haplotype for 167delT but the existence of several haplotypes for 30delG. Audiologic examination of carriers of the mutant alleles who had normal hearing revealed subtle differences in their otoacoustic emissions, suggesting that the expression of mutations in GJB2 may be semidominant.Conclusions: The high frequency of carriers of mutations in GJB2 (4.76 percent) predicts a prevalence of 1 deaf person among 1765 people, which may account for the majority of cases of nonsyndromic recessive deafness in the Ashkenazi Jewish population. Conservation of the haplotype flanking the 167delT mutation suggests that this allele has a single origin, whereas the multiple haplotypes with the 30delG mutation suggest that this site is a hot spot for recurrent mutations. [ABSTRACT FROM AUTHOR]