A PCR technique for the detection of Jaagsiekte sheep retrovirus in the blood suitable for the screening of ovine pulmonary adenocarcinoma in field conditions.

Ovine pulmonary adenocarcinoma (OPA) is a naturally occurring contagious lung neoplasia caused by jaagsiekte sheep retrovirus (JSRV). Although no specific circulating antibodies against the virus can be detected in infected sheep, JSRV proviral DNA sequences can be found in peripheral blood leukocytes (PBLs) in clinically affected and in a proportion of in contact animals. In this study, existing hemi-nested PCR procedure is compared with a new one-step PCR technique that was developed to minimise potential DNA contamination and reduce sample and reagent handling. Different blood preparations were assessed and the best results were achieved on DNA prepared from buffy coat. The sensitivity of this PCR was lower in JSRV infected sheep without lesions of OPA than in clinically affected sheep, which indicate that this PCR may not be not fully appropriate for screening of individual sheep, but rather to provide results at flock level. This PCR is the only currently available blood test for detection of JSRV infected sheep and may be useful in epidemiological studies and in control programmes of OPA.

The potentially insecticidal Narcissus pseudonarcissus lectin demonstrates age-related mitogenicity.

Lectins from monocotyledonous plants such as Narcissus pseudonarcissus (NPA) possess insecticidal properties and have the potential to increase pest resistance in transgenic crops. Therefore it is of interest to investigate the mitogenic properties of such lectins. Mononuclear cells purified from human umbilical cord and adult peripheral blood samples were stimulated with NPA and compared to phytohaemagglutinin as an example of a lectin from a dicotyledonous plant. Here we report that NPA is slightly mitogenic for adult human lymphocytes but mitogenicity is increased more than sevenfold for lymphocytes from umbilical cord blood. Similarly, NPA was found to be mitogenic for peripheral blood mononuclear cells (PBMC) from lambs and not adult sheep, supporting the age-related mitogenicity and indicating that further examination of the younger human population is warranted.