Overlap stimulation of primary and secondary B cells by cross-reacting determinants.

Experiments were carried out to test the validity of the hypothesis that postulated differences in the nature of the antigen receptors of primary and secondary B cells should be reflected in a greater specificity in primary B-cell stimulation (2). Enumeration of clonal precursors stimulated by either DNP-Hy, TNP-Hy, or a mixture of both antigens confirmed this hypothesis. Since the sum of primary B cells stimulated by DNP-Hy and TNP-Hy is approximately equal to the number stimulated by a mixture of both, overlap stimulation of primary B cells by these antigens could be considered negligible. In contrast, the stimulation of B cells from mice previously immunized with DNP-Hy showed extensive overlap of stimulation by DNP-Hy and TNP-Hy. Thus secondary B cells appear less fastidious in their affinity requirements for stimulation than primary B cells.

Law and practice in relation to coronial post mortems--a social perspective.

The coronial post mortem, might be described as a coercive process because it takes place by force of law and, subject to the safeguards which the law now recognizes, irrespective of the wishes of the family of the deceased or, indeed, any wishes expressed by the deceased in his or her lifetime. That process should therefore be considered in the context of the competing social and consequent legal imperatives that impact upon the decision to undertake an autopsy, the means by which it is undertaken and the extent of the process. The purpose of this paper is to examine those social imperatives, the legislative framework and case law including recent legislative reforms designed to meet these social imperatives, some of which have been recognised only in recent times. Recent developments in law and practice have had a significant impact on the social issues involved. Important scientific research has now been undertaken that demonstrates the value of radiological techniques particularly CAT scans and MRIs as a means of avoiding some of the social difficulties involved in the process and, at the same time, proving valuable forensic tools in many cases. The role of such processes will be discussed. References to legislation are references to the statutes of New South Wales unless otherwise stated.

Defining the heterogeneity of anti-tumor antibody responses.

Studies were undertaken to analyze the humoral in vivo and in vitro antibody response of BALB/c mice to a syngeneic MSV-induced tumor cell line. With a sensitive radioimmunoassay, sera obtained from individual progressor and regressor mice were shown to vary greatly in total tumor-specific antibody concentration as well as immunoglobulin class distribution of the antibody, but no significant difference existed between the groups of progressor and regressor mice as a whole. In addition, serum antibodies from all animals were shown to have extensive cross-reactivity against a variety of cell lines chosen to share one or more antigens with the cell line used for immunization. Conversely, when in vitro fragment cultures of splenic tissue from progressor and regressor mice were stimulated with tumor-related antigen, differences in responsiveness among normal, progressor, and regressor mice were observed. In addition, antibodies derived from fragment cultures displayed several different cross-reactivity patterns all of which were more restricted in specificity than serum antibodies.

In vitro effect of phagocyte cationic peptides on Coccidioides immitis.

Several cationic peptides that were isolated from rabbit granulocytes exerted fungicidal activity against arthroconidia of Coccidioides immitis in vitro. The fungicidal effect of the cationic peptides required at least 4-8 hr of contact between peptide and fungal cells and appeared to be dependent upon active fungal metabolism. The fungicidal activity was inhibited by increases in the tonicity of the growth medium but was not inhibited by changes in pH. These findings provide a potential mechanism whereby phagocytic cells may limit the spread of infection due to C. immitis.

In situ localization of T lymphocytes in disseminated coccidioidomycosis.

Immunohistochemical techniques using monoclonal antibodies to T lymphocyte subpopulations were used to characterize further the granulomas of disseminated coccidioidomycosis. Skin biopsy specimens from patients with disseminated coccidioidomycosis were studied and compared with tissues from experimentally infected mice. In human skin biopsy specimens and infected mouse tissues, discrete granulomata were seen in which T lymphocytes formed a peripheral mantle surrounding central aggregates of macrophages. This unusual pattern of granuloma formation may represent an ineffective host response because these individuals are unable to clear their infection. Because of the close similarity of immunopathology in both human and mouse infections, the mouse model should serve as a useful tool in elucidating the factors contributing to ineffective host responses in systemic fungal infections.