Expression of lipooligosaccharide (LOS) antigenic determinants during human gonococcal infection was studied in secretions from seven men with gonococcal urethritis. Five monoclonal antibodies with distinct gonococcal LOS specificities and an H.8 lipoprotein monoclonal antibody were used in combination with immunogold electron microscopic analysis. The LOS epitope defined by antibody 6B7 was present on all seven strains in secretions and after in vitro growth. Gonococci from six of seven patients, when grown in vitro, expressed the 6B4 LOS epitope. The 6B4 epitope is a Gal beta 1-4-GlcNAc residue, which is immunochemically similar to the precursor of the human erythrocyte i antigen. This epitope was found unmodified on gonococcal LOS in urethral secretions from two patients. The unmodified epitope could not be demonstrated on organisms in five secretions. Neuraminidase digestion exposed the 6B4 epitope on organisms in these secretions and increased the 6B4 epitope density in the two secretions, which contained the unmodified epitope. These studies indicate that in vivo modification by sialylation of gonococcal LOS Gal beta 1-4-GlcNAc residue occurs during human infection.

Raper & Thom (1949) in their Manual of the Penicillia separate species in this genus into four major sections, Monoverticillata, Asymmetrica, Biverticillata-Symmetrica and Polyverticillata. They subdivide each of the sections into a number of series so that the Biverticillata-Symmetrica section, for example, includes six such series among which, for the purpose of this communication, the following are of interest: the P. luteum series including P. wortmanni Klocker; the P. funiculosum series including P. iBlandicum Sopp; and the P. rugulo8um series including P. rugulo8um Thom. In common with other series in the Biverticillata-Symmetrica, strains in the three series mentioned produce yellow to orange or reddish colours in the aerial vegetative mycelium with a colony reverse in similar colours or occasionally dark purple-red to almost black.A number of crystalline colouring matters have been isolated here from strains of P. i8landicum (Howard & Raistrick, 1949, 1950, 1954a, and we now report similar investigations on the colouring matters of P. rugulo8um and P. wortmsnni. This work was commenced early in 1939 by one of us (J.B.) and resulted in the isolation, from a highly pigmented strain of P. rugulo8um, strain H.Z., recently isolated from natural sources and cultivated in the laboratory on Czapek-Dox solution, of considerable quantities of a beautifully crystalline, bright yellow colouring matter which was named rugulosin, since it had not been described previously.The work was discontinued later in the year and was not taken up again until 9 years later (Raistrick, 1949;Dacre, 1950). By this time the yield of rugulosin obtainable from P. rugulo8um strain H.Z. was very much smaller than that obtained previously, but two other strains of the same species, i.e. strains S.M. 1 and S.M. 14, which had not been kept in laboratory culture for so long a time, gave very considerable yields of the colouring matter. In this connexion it is of interest to note that, according to Raper & Thom (1949), while newly isolated strains of P. rugulo8um usuallRy sporulate freely and have a bright orange-red reverse, the same strains after being held in laboratory culture for a long time sporulate much less heavily and have an almost white reverse. No rugulosin could be detected in three such strains.The yields of crude crystalline rugulosin obtained by ether extraction of the dried and defatted mycelium from the three strains of P. ruguloumm used in its preparation were considerable and amounted to 21 % ofthe dry weight ofthe mycelium of strain S.M. 1, 10-13 % from strain S.M. 14 and 7-8 % from strain H.Z. In addition, small amounts of crystalline rugulosin were isolated from strain P. 50 and from strain N.R.R.L. 1045 which is a direct descendant of Dr Charles Thom's original type strain.Rugulosin has also been isolated from cultures of P. wortmanni grown on Czapek-Dox solution. Hence, this species, which has bright yellow perithecia embedded in yellowish orange mycelium, links the perithecia-producing P. luteum series with strains ...

Cryptococcus neoformans, an opportunistic fungal pathogen, often causes serious and life-threatening infections in immunocompromised hosts as well as in normal individuals. In the present study, purified cryptococcal capsular polysaccharide antigen was examined for its effect on several parameters of immune response and its ability to induce immune response to itself. Injection of the antigen into mice resulted in a dose-related specific antibody response which was detected at the individual antibody plaque-forming-cell level by a hemolytic assay in gel. Relatively low doses of cryptococci induced a maximal response, whereas higher doses resulted in a markedly depressed response. The antibody response to the cryptococcal capsular polysaccharide antigen appeared to be T cell independent and regulated by suppressor T cells, since mice injected with antilymphocyte serum or antithymocyte serum showed specific antibody responses to the antigen that were higher than those of untreated mice. It also markedly affected the in vitro mixed-lymphocyte reaction when added to cultures of mouse spleen cells being challenged in vitro with mitomycin C-treated allogeneic cells. The lower doses stimulated the response, whereas higher doses suppressed it. The macrophage response to yeast cells but not opsonized sheep erythrocytes was also modulated by the cryptococcal antigen.

A NUMBER of polyhydroxyanthraquinones, all of which are derivatives of 2methylanthraquinone, have been reported from these laboratories as metabolic products of different species of moulds. They are: helminthosporin, 4:5:8-trihydroxy-2-methylanthraquinone, from Helminthosporium gramineum Rabenhorst [