DNA Extraction Columns Contaminated with Murine Sequences

Abstract

Sequences of the novel gammaretrovirus, xenotropic murine leukemia virus-related virus (XMRV) have been described in human prostate cancer tissue, although the amounts of DNA are low. Furthermore, XMRV sequences and polytropic (p) murine leukemia viruses (MLVs) have been reported in patients with chronic fatigue syndrome (CFS). In assessing the prevalence of XMRV in prostate cancer tissue samples we discovered that eluates from naïve DNA purification columns, when subjected to PCR with primers designed to detect genomic mouse DNA contamination, occasionally gave rise to amplification products. Further PCR analysis, using primers to detect XMRV, revealed sequences derived from XMRV and pMLVs from mouse and human DNA and DNA of unspecified origin. Thus, DNA purification columns can present problems when used to detect minute amounts of DNA targets by highly sensitive amplification techniques.

Lack of evidence for human infection with Xenotropic murine leukemia virus-related virus in the Brazilian Amazon basin

“…We also found no evidence of XMRV infection in prostate tumor samples, contradicting the results of previous studies that found an apparent association between this retrovirus and prostate cancer [1][2][3][4] . Similar negative results were attributed to the failure of PCR procedures 13,[15][16][17] . However, it is important to note that in the present study, nested and real time PCR were used, and both procedures were effective in detecting proviral DNA of HIV-1 and HTLV-1/2 in several different groups, even when viral copy numbers were extremely low [24][25][26][27] .…”

“…Potential confounding factors include: a) the diffi culty of reproducing results obtained for both the general population and patients with PC or CFS; b) the origin of the virus in relation to endogenous murine leukemia virus; c) the contamination of human blood and tissue samples with murine deoxyribonucleic acid (DNA); and d) the contamination of commercial polymerase chain reaction (PCR) reagents with potential sources of false-positive results [12][13][14] .…”

“…The results of subsequent studies involving PC and CFS patients failed to show detectable XMRV or found extremely low levels of proviral DNA in the samples, indicating that PCR detection of the virus is not always feasible or reliable 13,[15][16][17] .…”

“…The most likely explanation for false positive results is contamination of commercial PCR reagents [12][13][14] . Additionally, Tuke et al 28 proposed that a specifi c Taq DNA polymerase may contain monoclonal mouse antibodies with varying quantities of murine DNA.…”

XMRV ist nicht human-pathogen und hat keine Bedeutung für die Sicherheit von Blut und Blutprodukten

“…Die Quelle der Verunreinigung konnte in einigen Fällen identifiziert werden [15]. In DNA-Extraktionssäulen und in kommerziellen Polymerasepräparationen wurden Spuren muriner DNA nachgewiesen, die möglicherweise durch monoklonale Antikörper bei Reinigung der Polymerase eingebracht wurden [18,19].…”