Prevalence and Quantitation of Species C Adenovirus DNA in Human Mucosal Lymphocytes

Abstract

The common species C adenoviruses (serotypes Ad1, Ad2, Ad5, and Ad6) infect more than 80% of the human population early in life. Following primary infection, the virus can establish an asymptomatic persistent infection in which infectious virions are shed in feces for several years. The probable source of persistent virus is mucosa-associated lymphoid tissue, although the molecular details of persistence or latency of adenovirus are currently unknown. In this study, a sensitive real-time PCR assay was developed to quantitate species C adenovirus DNA in human tissues removed for routine tonsillectomy or adenoidectomy. Using this assay, species C DNA was detected in Ficoll-purified lymphocytes from 33 of 42 tissue specimens tested (79%). The levels varied from fewer than 10 to greater than 2 ؋ 10 6 copies of the adenovirus genome/10 7 cells, depending on the donor. DNA from serotypes Ad1, Ad2, and Ad5 was detected, while the rarer serotype Ad6 was not. When analyzed as a function of donor age, the highest levels of adenovirus genomes were found among the youngest donors. Antibody-coated magnetic beads were used to purify lymphocytes into subpopulations and determine whether viral DNA could be enriched within any purified subpopulations. Separation of T cells (CD4/8-expressing and/or CD3-expressing cells) enriched viral DNA in each of nine donors tested. In contrast, B-cell purification (CD19-expressing cells) invariably depleted or eliminated viral DNA. Despite the frequent finding of significant quantities of adenovirus DNA in tonsil and adenoid tissues, infectious virus was rarely present, as measured by coculture with permissive cells. These findings suggest that human mucosal T lymphocytes may harbor species C adenoviruses in a quiescent, perhaps latent form.The common adenovirus serotypes of species C (Ad1, Ad2, Ad5, and Ad6) cause roughly 5% of symptomatic upper respiratory tract (5) and 15% of lower respiratory tract (3) infections in children younger than 5 years.

Adenovirus DNA is detected at increased frequency in Guthrie cards from children who develop acute lymphoblastic leukaemia

“…Of 1187 unique samples in four large studies, 64 (5.4%) contained adenoviral DNA ( Van den Veyver et al, 1998;Wenstrom et al, 1998;Baschat et al, 2003;Reddy et al, 2005), which compares favourably with 6% adenovirus DNA-positive samples among the normal controls in the present study (Table 1). And, as is the case with children infected post-natally, adenoviral DNA is retained in latently infected T lymphocytes for years following primary infection (Garnett et al, 2002). Thus, the finding of species C adenovirus in neonatal blood spots is evidence of prenatal infection, as is the case for other prenatal viral infections (Barbi et al, 1996;Johansson et al, 1997;Fischler et al, 1999).…”

“…Both assays amplified DNA from all species C serotypes, but not from members of other adenovirus species (A, B, D, E, and F). In some cases, samples were also tested with a quantitative real-time PCR assay (Garnett et al, 2002). As a control, PCR with a set of HLA-DQ alpha primers was performed as described (Saiki et al, 1986).…”

“…The common, endemic species C adenoviruses (serotypes 1, 2, 5, and 6) normally cause respiratory tract infections in young children (Brandt et al, 1969;Avila et al, 1989) and persistent infection of lymphoid tissues (Garnett et al, 2002). We investigated whether adenovirus infections could be correlated with ALL by studying Guthrie cards from children who later developed ALL and healthy controls.…”

Experimental infections of humans with wild-type adenoviruses and with replication-competent adenovirus vectors: replication, safety, and transmission

“…62 In a recent study, Ad DNA was frequently detected (by real-time PCR) in lymphocytes purified from tonsils and adenoids (79%) despite the fact that infectious virus was rarely observed in these same samples. 63 Using antibody depletion methods, these authors demonstrated that Ad DNA was enriched in CD8/CD4-expressing and/ or CD3-expressing T cells, while B cells expressing CD19 were devoid or depleted of Ad DNA. 63 However, as described above, lung epithelial cells may also be a site of latent/persistent Ad infection.…”

An ex vivo loop system models the toxicity and efficacy of PEGylated and unmodified adenovirus serotype 5 in whole human blood

“…Ad5 is a common respiratory tract virus and consequently, a high proportion of the population has immunological memory in the form of anti-Ad5 antibodies. 13 In the US, the prevalence of neutralizing antibodies against Ad5 is between 33 and 60%. 14,15 Following the first dose of systemic adenoviral administration, 100% of patients test positive for anti-adenovirus antibodies and this is likely to be the case whichever serotype that is used.…”