Broadly targeted human cytomegalovirus-specific CD4+ and CD8+ T cells dominate the memory compartments of exposed subjects.

Human cytomegalovirus (HCMV) infections of immunocompetent hosts are characterized by a dynamic, life-long interaction in which host immune responses, particularly of T cells, restrain viral replication and prevent disease but do not eliminate the virus or preclude transmission. Because HCMV is among the largest and most complex of known viruses, the T cell resources committed to maintaining this balance have never been characterized completely. Here, using cytokine flow cytometry and 13,687 overlapping 15mer peptides comprising 213 HCMV open reading frames (ORFs), we found that 151 HCMV ORFs were immunogenic for CD4(+) and/or CD8(+) T cells, and that ORF immunogenicity was influenced only modestly by ORF expression kinetics and function. We further documented that total HCMV-specific T cell responses in seropositive subjects were enormous, comprising on average approximately 10% of both the CD4(+) and CD8(+) memory compartments in blood, whereas cross-reactive recognition of HCMV proteins in seronegative individuals was limited to CD8(+) T cells and was rare. These data provide the first glimpse of the total human T cell response to a complex infectious agent and will provide insight into the rules governing immunodominance and cross-reactivity in complex viral infections of humans.

Serum antibodies to lipophilin B detected in late stage breast cancer patients.

Lipophilin B mRNA is overexpressed in approximately 70% of breast tumors and shows a high degree of correlation with the mRNA expression profile of mammaglobin. This is further supported by the recent finding that, like other members of the secretoglobulin-uteroglobin family, mammaglobin and lipophilin B form a heteroduplex. The studies described show that there are pre-existing antibodies to lipophilin B peptide in the sera of breast cancer patients with different stages and grade of tumor and that this response is different from that seen to recombinant mammaglobin and native mammaglobin-lipophilin B complex. The highest titers were observed in later stage tumors. In addition, low levels of antibody were also seen in some patients with prostate and ovarian cancers, consistent with lipophilin B mRNA expression in these tumors at lower abundance than in breast tumors. In contrast, lipophilin B antibodies were absent in 20 healthy donor sera and 30 lung cancer sera. A polymorphism identified in Lipophilin B did not appear to influence human sera reactivity. The data indicate that humoral immune responses to lipophilin B may serve as a diagnostic indicator, particularly for breast cancer.

Identification of Babesia microti-specific immunodominant epitopes and development of a peptide EIA for detection of antibodies in serum.

BACKGROUND: Babesia microti is a tick-borne agent that is increasingly implicated in transfusion-acquired infection, especially in immunocompromised and elderly recipients. To develop a test that can detect antibody responses to B. microti, peptide epitopes identified in two serocomplementary B. microti-specific antigens were used in a prototype EIA. STUDY DESIGN AND METHODS: A prototype peptide EIA was used to detect B. microti-specific antibodies in 15 sera taken before infection and 107 taken after infection from 59 individuals with known tick-borne infections previously confirmed by other methods. Three additional groups of samples were also tested: a proficiency panel of 18 sera positive for B. microti by IFA, 38 sera from blood donors confirmed positive by IFA, and 30 sera from random blood donors. RESULTS: The combination peptide detected 98 out of 107 sera taken after infection that were IgG blot positive (4 equivocal). This included all 12 samples that were PCR positive and six sera from smear-negative patients that were confirmed positive by PCR, immunoblot, or IFA. Of the IgG blot-positive specimens that were equivocal (four specimens) or did not react (nine specimens) by EIA, most had low IFA titers consistent with previous exposure. In a second evaluation, 15 out of 15 Babesia IFA-positive sera and 3 out of 3 Babesia-Ehrlichia IFA-positive sera were positive, whereas sera from 30 random donors were negative. Finally, of 38 IFA-positive blood-donor samples, 35 were positive by peptide EIA. The three EIA-negative sera were Western blot negative. CONCLUSION: Reactivity of the B. microti-specific peptide EIA shows a high correlation with IFA, PCR, and B. microti immunoblot in confirmed B. microti cases. The peptide EIA may be the most suitable B. microti infection test for adaptation to the blood bank environment if testing for B. microti is required in the future.