Augmentation of natural killer cell activity in vitro against tumor cells by wild plants from Jordan.

Thirteen aqueous extracts prepared from Jordanian plants, that are currently used in traditional medicine to treat various types of cancer, were tested in mice for their ability to augment natural killer (NK) cell function in vitro in generating cytotoxicity against YAC tumor targets. Lymphoid cells at a concentration of 5x10(6)/ml were incubated in medium alone or in medium containing different dilutions of either plant extract or purified interferon alpha for 20 h and tested for NK activity. Maximum NK activity (62. 3%) was obtained at 1:50 dilution of Nigella sativum fresh aqueous extract, 48.5% at 1:100 dilution for Allium sativum (and 38.3% at 1:50 dilution for Onopordum acanthium. Fresh aqueous plant extracts appeared to be more potent than old dried aqueous extract or ethanolic extracts. NK augmentation by plant extracts using nylon wool non-adherent spleen cells was slightly higher than the whole spleen cells.

Protective immunity against Newcastle disease: the role of cell-mediated immunity.

The role of cell-mediated immunity (CMI) in protection of birds from Newcastle disease was investigated by two different strategies in which only Newcastle disease virus (NDV)-specific CMI was conveyed without neutralizing antibodies. In the first strategy, selected 3-wk-old specific-pathogen-free (SPF) birds were vaccinated with either live NDV (LNDV), ultraviolet-inactivated NDV (UVNDV), sodium dodecyl sulfate-treated NDV (SDSNDV), or phosphate-buffered saline (PBS) (negative control) by the subcutaneous route. Birds were booster vaccinated 2 wk later and challenged with the velogenic Texas GB strain of NDV 1 wk after booster. All vaccinated birds had specific CMI responses to NDV as measured by a blastogenesis microassay. NDV neutralizing (VN) and hemagglutination inhibition (HI) antibody responses were detected in birds vaccinated with LNDV and UVNDV. However, birds vaccinated with SDSNDV developed antibodies that were detected by western blot analysis but not by the VN or HI test. Protection from challenge was observed only in those birds that had VN or HI antibody response. That is, birds with demonstrable CMI and VN or HI antibody response were protected, whereas birds with demonstrable CMI but no VN or HI antibody response were not protected. In the second strategy, birds from SPF embryos were treated in ovo with cyclophosphamide (CY) to deplete immune cells. The birds were monitored and, at 2 wk of age, were selected for the presence of T-cell activity and the absence of B-cell activity. Birds that had a significant T-cell response, but not a B-cell response, were vaccinated with either LNDV, UVNDV, or PBS at 3 wk of age along with the corresponding CY-untreated control birds. The birds were booster vaccinated at 5 wk of age and were challenged with Texas GB strain of NDV at 6 wk of age. All birds vaccinated with LNDV or UVNDV had a specific CMI response to NDV, VN or HI NDV antibodies were detected in all CY-nontreated vaccinated birds and some of the CY-treated vaccinated birds that were found to have regenerated their B-cell function at 1 wk postbooster. The challenge results clearly revealed that CY-treated birds that had NDV-specific CMI and VN or HI antibody responses to LNDV or UVNDV were protected, as were the CY-nontreated vaccinated birds. However, birds that had NDV-specific CMI response but did not have VN or HI antibodies were not protected from challenge. The results from both strategies indicate that specific CMI to NDV by itself is not protective against virulent NDV challenge. The presence of VN or HI antibodies is necessary in providing protection from Newcastle disease.

Protective immunity against Newcastle disease: the role of antibodies specific to Newcastle disease virus polypeptides.

Studies were performed to determine if passive immunization with hyperimmune sera generated to specific Newcastle disease virus (NDV) proteins conferred protection against virus challenge. Six groups of 3-wk-old chickens were passively immunized with antiserum against either hemagglutinin-neuraminidase/fusion, (HN/F) protein, nucleoprotein/phosphoprotein (NP/P), Matrix (M) protein, a mixture of all NDV proteins (ALL), intact ultraviolet-inactivated NDV (UVNDV), or negative sera. Blood samples were collected 2 days postimmunization, and the birds were challenged with Texas GB strain of NDV. Antibody titers were detected from those recipient birds that had received the antisera against the HN/F, ALL, or UVNDV by a hemagglutination inhibition test, an enzyme-linked immunosorbent assay (ELISA), and a virus neutralization test. Antibodies were detected only by the ELISA from the birds that had received antisera against NP/P and M protein. Antibody titers in the recipient birds dropped by two dilutions (log2) after 2 days postinjection. Birds passively immunized with antisera against HN/F, ALL, and UVNDV were protected from challenge, whereas chickens passively immunized with antisera against NP/P and M protein and specific-pathogen-free sera developed clinical signs of Newcastle disease. The challenge virus was recovered from the tracheas of all passively immunized groups. The presence of neutralizing antibodies to NDV provided protection from clinical disease but was unable to prevent virus shedding from the trachea.

A technique for inducing B-cell ablation in chickens by in ovo injection of cyclophosphamide.

The effect of cyclophosphamide (CY) treatment in ovo on avian B and T cells was studied. CY was injected in ovo on the 16th, 17th, and 18th days of incubation. Blood samples were collected periodically from CY-treated and nontreated birds after hatch and were used to measure blood lymphocyte responses to the T-cell and B-cell mitogens, concanavalin A and lipopolysaccharide (LPS), respectively. Additionally, flow cytometric analysis was used to determine the presence of B and T cells in peripheral blood, and birds were vaccinated with Newcastle disease virus (NDV) antigen at 3 wk of age and booster vaccinated at 5 wk of age. CY treatment reduced hatchability by 35%-40%, increased mortality by 3%-5% within the first 2 wk of life, and induced a significant retardation in body weight gains. At 2 wk of age, approximately 50% of CY-treated birds were devoid of B-cell mitogenic responsiveness while demonstrating significant T-cell mitogenic responsiveness. However, B-cell responses were observed at 4 and 6 wk from a small percentage of birds that were originally T-cell responsive and B-cell nonresponsive at 2 wk of age. Flow cytometric analysis of peripheral blood lymphocytes revealed that CY-treated birds had significantly less B cells (or were devoid of B cells) than the corresponding nontreated control birds. However, no significant difference in the T-cell percentage was observed between CY-treated and nontreated birds. CY-treated birds did not produce detectable antibodies specific for NDV during the first and second weeks postvaccination, as demonstrated by hemagglutination inhibition assay. However, antibodies were detected in some CY-treated birds 10 days postbooster. Those antibody-positive birds were found to be the same birds that had subsequently responded to the LPS mitogen on the blastogenesis microassay. This study indicates the importance of monitoring the B- and T-cell responses in CY-treated birds to identify those birds in which B-cell regeneration may have occurred.

A rapid virus neutralization assay for Newcastle disease virus with the swine testicular continuous cell line.

Five continuous cell lines, swine testicular (ST), human rectal tumor (HRT 18), fetal rhesus monkey kidney (MA104), bovine turbinate (BT), and quail tracheal (QT35), were evaluated and compared with chicken embryo fibroblasts (CEFs) for their ability to propagate B1 or Texas GB strains of Newcastle disease virus (NDV). The NDV Texas GB strain replicated in all the continuous cell lines used in this study. Only the ST and QT35 cells produced a cytopathic effect (CPE) similar to that produced in CEFs. However, the ST cell line remained attached while displaying CPE, whereas infected QT35 cells detached, as did the CEFs. The B1 strain of NDV replicated in ST cells, MA104 cells, and CEFs but with less CPE as compared with the Texas GB strain. Pretreatment with trypsin did not enhance CPE with either NDV strain at the level tested. Sera evaluated for neutralizing antibody titers to NDV were significantly higher in titer when the ST cell line was used and compared with CEFs. A high correlation was found between the microscopic examination and the tetrazolium dye (MTT) microassay methods for determining the viral neutralization endpoint, thus suggesting the ST cell line and MTT microassay could be used as an alternative to CEFs and microscopic examination for evaluating neutralizing antibodies titers to NDV.

Technical and editorial administration of a World-Wide-Web site during a period of rapid growth: the OncoLink experience.

OncoLink is a cancer information resource on the World-Wide-Web (WWW) that provides a wide variety of information for cancer patients and healthcare providers. Since its introduction in March, 1994 it has enjoyed success as demonstrated by an over 31-fold increase in usage as of February, 1996. Current utilization exceeds 1.1 million accesses per month. The content of OncoLink has also expanded greatly, with new items being added daily. In addition, OncoLink has been the recipient of numerous awards from a variety of agencies and organizations. During this period of rapid growth, the complexity of managing and maintaining OncoLink has likewise increased. This work may be divided into three categories: content editing, technical (or production) editing, and web site maintenance. Consequently, we have developed numerous administrative procedures to handle this workload. After implementing these new administrative strategies, we were able to greatly reduce the need for face-to-face meetings of our Editorial and Production Staffs. This paper describes our experience with developing efficient strategies for managing the daily operation of OncoLink during a period of rapid growth.