The Australian journal of experimental biology and medical science最新文献

Ross River virus (RRV) strains T48 and SC18006 produced a self-limited cytopathic infection of primary and passaged human synovial cell culture. Extracellular (EC) virus titres reached peak levels at 2 days in cell lines and at 4 days in primary cultures, ranging between 10(4.5) and 10(6.6) fluorescent focus-forming units (ffu)/ml. Thereafter titres declined rapidly to undetectable levels at 10-12 days. The proportion of adherent cells showing virus antigen exceeded 60% at 3 days and decreased in all cultures to less than 1/500 after 12 days. Cytopathic effects (CPE) were greatest at 4-8 days and destroyed between 25 and 75% of the cell layer, with subsequent partial regeneration by division of surviving cells. In contrast to rubella virus infection of synovial cells, cultures at 32 degrees and 37 degrees revealed only minor differences and persistent infection was not established. CPE were more extensive at 37 degrees in nearly all synovial cell cultures and in Vero cultures. At 37 degrees synovial cells infected with T48 strain produced higher maximum titres and were more extensively infected than at 32 degrees.

A tumour-associated antigen has been identified which is expressed on both BALB/c plasmacytomas and T lymphomas, but which does not induce a detectable cell-mediated immune response in the strain of origin of the tumours. The (BALB/c x C57BL) F1 hybrid, however, makes a readily detectable response both in vivo and in vitro in vitro experiments with various BALB/c H-2 F1 cogenic mice indicated that the genetic control of the response was not H-2 linked, and was associated with other C57BL genes.

The frequency of haemoglobin types in several major breeds of cattle in northern Austrailia was determined. In all Boss taurus cattle examined only the three common bovine haemoglobin types (AA, AB, BB) were found. F2 Africander cross-breeds showed only AA patterns. The frequency of haemoglobin B was significantly higher in Bos indicus type cattle than in Bos taurus breeds. In the pure breed Banteng cattle (Bos banteng) three genotypes (BB, CB, CC) were present. The eleven buffaloes types each showed two haemoglobins (A1 and A2) in proporotions of 71 to 29 respectively.

A study of potentially zoonotic infections was carried out on 351 rodents trapped in north-eastern Queensland. Their ecosystems included towns, agricultural and livestock areas, wookland and rainforest. Nine serotypes of salmonellae were obtained from asymptomatic carries in predominantly settled locations. Two strains of Ps. pseudomallei occurred in rainforest near Innisfail and one on a cattle property adjacent to Townsville. Ps. aeruginosa caused bronchopneumonia in one animal from Townsville harbour. Ifection by leptospirae of six serogroups and seven serovars were identified by serological or cultural examinations. Enzootic foci occurred on the Mount Spec rainforest where celledoni and australis were being excreted by rats adjacent to the Paluma dam system. In addition to the scrub typhus locations at Rocky Creek, Atherton Tableland and Bullocky Creek, near Ingham, which were confirmed, a new focus of infection by R. tsutsugamushi was identified at El Arish near Tully. Water rat (H. chrysogaster) at Townsville harbour constituted a reservoir of toxoplasmosis. In addition to the known human pathogenic helminths H. nana and H. diminuta, localized foci of hookworms (Ancylostoma spp.) were found. Histological evidence of cytomegalic disease of the salivary glands or kidneys was a common finding.

Early, specific concomitant immunity to each of four tumours was inhibited by treatment with silica or carrageenan. Late, non-specific concomitant immunity was, with one exception, not inhibited by these agents. Treatment of non-immune mice with silica at certain critical periods before challenge promoted the growth of four of six syngeneic methylcholanthrene-induced tumours in their feet. Treatment with carrageenan was much less effective. Early and late concomitant immunity were inhibited by one or more agents inhibiting delayed-type hypersensitivity: irradiation, niridazole and reserpine. Irradiation of non-immune mice did not effect the growth of tumours in their feet. Treatment of non-immune mice with niridazole or reserpine actually inhibited the growth of some tumours. It is suggested that (a) mice offer some natural resistance to tumour growth, macrophages perhaps being effectors; (b) some tumour isografts may survive only if an inflammatory reaction occurs; (c) mechanisms akin to those of delayed-type hypersensitivity operate in the expression of concomitant immunity; (d) macrophages are important in early, specific concomitant immunity, but perhaps less so in the late non-specific phase.

Three different type A influenza viruses have been isolated from pelagic birds nesting on islands of the Great Barrier Reef. One of these, isolated in 1972, was of subtype Hav6Nav5. The other two, which are described in this paper, were isolated in 1975 and belonged to subtypes Hav5Nav2 and Hav3Nav6. Of eight isolates of the latter virus, seven were recovered from cloacal swabs and only one from the trachea.