The efficacy of vaccination with Toxoplasma gondii recombinant GRA4 (rGRA4) and ROP2 (rRPO2) proteins and a mix of both combined with alum were evaluated in C57BL/6 and C3H mice. In C57BL/6 mice, rGRA4 and rGRA4-rROP2 immunizations generated similar levels of immunoglobulin G1 (IgG1) and IgG2a isotypes against GRA4, whereas immunizations with rROP2 and the mix induced a predominant IgG1 production against ROP2. All groups of C3H vaccinated mice exhibited higher levels of IgG1 than IgG2a. rGRA4-stimulated splenocytes from vaccinated mice produced primarily gamma interferon while those stimulated with rROP2 produced interleukin-4. Challenge of rGRA4-or rGRA4-rROP2-vaccinated mice from both strains with ME49 cysts resulted in fewer brain cysts than the controls, whereas vaccination with rROP2 alone only conferred protection to C3H mice. Immunization with a plasmid carrying the entire open reading frame of GRA4 showed a protective level similar to that of rGRA4 combined with alum. These results suggest that GRA4 can be a good candidate for a multiantigen anti-T. gondii vaccine based on the use of alum as an adjuvant.

In a retrospective study of 45 cases of rheumatoid arthritis selected for their severity or for elevated titers of rheumatoid factor, unexplained eosinophile counts of 5% or greater were encountered in 40%. Certain extra‐articular manifestations of rheumatoid arthritis were found in higher incidence in the group of patients with eosinophilia. The most notable of these were vasculitis, pleuropericarditis, pulmonary fibrosis and subcutaneous nodules. The eosinophilia was present for variable periods of time, sometimes persisting at elevated levels for several years or alternatively appearing in brief episodes. In a number of patients, the appearance in time of some extra‐articular manifestations was coincident with eosinophilia. Two patients had extreme elevations in the number of eosinophiles. The eosinophiles of one patient, studied in detail, showed inclusions, which by immunofluorescent microscopy, contained γG‐globulin, γM‐globulin and rheumatoid factor. The serum of this patient when incubated with another eosinophile preparation induced the formation of inclusions. Various mechanisms were discussed in which the eosinophilia is related to possible immune events occurring in the course of rheumatoid arthritis.