A phylogenetic analysis of the mycoplasmas: basis for their classification.

Small-subunit rRNA sequences were determined for almost 50 species of mycoplasmas and their walled relatives, providing the basis for a phylogenetic systematic analysis of these organisms. Five groups of mycoplasmas per se were recognized (provisional names are given): the hominis group (which included species such as Mycoplasma hominis, Mycoplasma lipophilum, Mycoplasma pulmonis, and Mycoplasma neurolyticum), the pneumoniae group (which included species such as Mycoplasma pneumoniae and Mycoplasma muris), the spiroplasma group (which included species such as Mycoplasma mycoides, Spiroplasma citri, and Spiroplasma apis), the anaeroplasma group (which encompassed the anaeroplasmas and acholeplasmas), and a group known to contain only the isolated species Asteroleplasma anaerobium. In addition to these five mycoplasma groups, a sixth group of variously named gram-positive, walled organisms (which included lactobacilli, clostridia, and other organisms) was also included in the overall phylogenetic unit. In each of these six primary groups, subgroups were readily recognized and defined. Although the phylogenetic units identified by rRNA comparisons are difficult to recognize on the basis of mutually exclusive phenotypic characters alone, phenotypic justification can be given a posteriori for a number of them.

Freezing and rejuvenation of human O erythrocytes for use in the immune adherence hemagglutination test.

A method was established to freeze selected human O erythrocytes and to thaw them as necessary for use in the immune adherence hemagglutination test. This method ensured interrun reproducibility and eliminated the necessity to screen blood donors (fresh cells) for acceptable C3b receptor site sensitivity.

Detection of herpes simplex virus in clinical specimens by an enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) for the detection of herpes simplex virus is described that can be performed in approximately four hours. The test, which does not require specialized equipment and uses relatively inexpensive, commercially available reagents, detected herpes simplex virus in 51% of specimens found to be positive by a time-consuming cell culture technic. The ELISA test compared favorably with a direct immunofluorescence method that detected HSV in only 1% of the cell culture-positive specimens. The ELISA test was readily carried out even with specimens unsuitable for cell culture and did not require cellular material as is the case with immunofluorescence technics. An advantage of the ELISA test for herpes simplex virus over the cell culture method was the detection of nonviable virus.

Studies of human anti-gamma-globulin factors reacting with pepsin-digested gamma-globulins.

Many sera from normal individuals as well as patients with various disease states contain agglutinating antibodies which show specificity for antigenic determinants of gamma-globulin revealed by pepsin digestion at pH 4.1. Sera containing such agglutinating activity as well as sera negative for these agglutinators contain low molecular weight (3S-5S) components of slow gamma-mobility which inhibit these agglutination reactions. Low molecular weight inhibitors show both auto- and isospecificity, and are antigenically related to the 5S pepsin fragment of gamma-globulin. A common situation is thereby revealed in which human anti-gamma-globulin antibodies showing specificity for pepsin-digested gamma-globulins are present in serum along with low molecular weight gamma-globulin components capable of inhibition. Autoreactivity or autospecificity of such anti-gamma-globulin factors is a phenomenon shared by both normal human sera and sera from patients with various disease states.