Cohen JI, Fauci AS, Varmus H, Nabel GJ

Cohen JI, Fauci AS, Varmus H, Nabel GJ. age-matched, chronically infected individuals. Antibody-dependent cell-mediated phagocytosis (ADCP) was rarely detected during AIM (4 of 24 individuals; 17%) but was generally detected during CONV (19 of 24 individuals; 79%). The majority (83%) of Dipsacoside B samples taken during AIM neutralized contamination of main B cells; all samples obtained at 6 months postdiagnosis neutralized EBV contamination of cultured and main target cells. Deep sequencing revealed interpatient gp350 sequence variance but conservation of the CR2-binding site. The levels of gp350-specific neutralizing activity directly correlated with higher peripheral blood EBV DNA levels during AIM and a greater evolution of diversity in gp350 nucleotide sequences from AIM to CONV. In summary, we conclude that this viral weight and EBV gp350 diversity during early contamination are associated with the development of neutralizing antibody responses following AIM. IMPORTANCE Antibodies against viral surface proteins can blunt the spread of viral contamination by covering viral particles, mediating uptake by immune cells, or blocking interaction with host cell receptors, making them a desirable component of a sterilizing vaccine. The EBV surface protein gp350 is usually a major target for antibodies. We statement the detection of EBV gp350-specific antibodies capable of neutralizing EBV contamination < 0.0001). The gp350-specific IgG levels measured during CONV were much like those measured in age-matched Dipsacoside B chronically infected (CHRON) individuals (Fig. 1A; median, 17,728 MFI; IQR, 11,825 MFI; Mann-Whitney test, = 0.96). EBV gp350-binding antibodies were detected primarily in the IgG1 (13 patients; 54%) and IgG3 (16 patients; 67%) fractions of plasma during AIM; IgG2 gp350-binding antibodies were detected in only 6 (25%) patients during AIM. gp350-specific IgG1, IgG2, and IgG4 binding antibody titers increased significantly from AIM to CONV (= 0.0001, = 0.034, and = 0.0001, respectively) to levels equal to those in CHRON individuals (Fig. 1B, ?,C,C, and ?andE).E). gp350-specific IgG3 binding antibody titers were significantly lower in CHRON individuals than during CONV (Fig. 1D) Dipsacoside B (< 0.001). Open in a separate windows Dipsacoside B FIG 1 Levels of EBV gp350-binding immunoglobulin (IgG) during AIM, CONV, and chronic EBV contamination. IgG was isolated from your serum of 24 patients during main EBV contamination (AIM) and 6 months later (during CONV). Binding of gp350 was compared to that in 12 age-matched chronically infected individuals (CHRON) and 12 age-matched EBV-seronegative individuals (Sero NEG). Binding of total individual IgG, as well as that of each IgG subclass, to EBV B95.8 gp350 (aa 4 to 440), was determined by detection of fluorescently labeled secondary antibodies. % Pos, percentage of individuals who were positive (indicated on the bottom line of each panel). values were determined by the Mann-Whitney and Wilcoxon matched-pairs signed-rank assessments. *, < 0.05; **, < 0.01; ?, < 0.001. Patient IgG mediates ADCP during CONV. Antibody-dependent cell-mediated phagocytosis (ADCP) activity was detected in the plasma-derived IgG of only 4 (17%) individuals with AIM CR6 but was detected in the plasma-derived IgG of 19 (79%) individuals during CONV (median phagocytosis score, 211,941; IQR of the phagocytosis score, 109,561; AIM versus CONV, < 0.0001) (Fig. 2A) at levels much like those in age-matched CHRON individuals (median phagocytosis score, 227,150; IQR Dipsacoside B of the phagocytosis score, 109,199; CONV versus CHRON individuals, was not significant). Open in a separate windows FIG 2 IgG from EBV-infected donors stimulates ADCP in cultured phagocytes. (A) Patient IgG samples were used to stimulate phagocytosis of gp350-coated microbeads by THP-1 cells. Data for 24 matched patient samples obtained during AIM and CONV, 12 age-matched chronically infected individuals (CHRON), and 12 age-matched serologically EBV-negative donors (Sero NEG) are included. % Pos, percentage of individuals who were positive (indicated on the bottom collection). ?, < 0.001; NS, not significant. (B to F) Correlations between phagocytosis scores and total anti-gp350 IgG, anti-gp350 IgG1, anti-gp350 IgG2, anti-gp350 IgG3, or anti-gp350 IgG4 relative titers (phagocytosis score versus relative MFI). Results only for samples obtained from 19 individuals during CONV and 11 CHRON individuals positive for ADCP activity are shown. values were determined by the Mann-Whitney and Wilcoxon matched-pairs signed-rank assessments. A positive correlation between total anti-gp350 IgG levels and ADCP activity was observed in samples obtained during CONV and in CHRON individuals (19 samples obtained during CONV and 11 samples from CHRON individuals; Spearman value = 0.480, < 0.01) (Fig. 2B). ADCP activity was also associated with anti-gp350 IgG1 levels but did not reach significance (=.