Absence of lung immunopathology following respiratory syncytial virus (RSV) challenge in mice immunized with a recombinant RSV G protein fragment

The relative immunopathogenic potential of a recombinant fusion protein inc orporating residues 130-230 of respiratory syncytial virus (RSV-A) G protei n (BBG2Na), formalin-inactivated RSV-A (FI-RSV), and phosphate-buffered sal ine (PBS) was investigated in mice after immunization and RSV challenge. FI -RSV priming resulted in massive infiltration of a cells and activated CD4( +) and CD8(+) T lymphocytes in mediastinal lymph nodes (MLN) and lungs, whe re eosinophilia and elevated IFN-gamma, IL-2, -4, -5, -10, and -13 mRNA tra nscripts were also detected. PBS-primed mice showed only elevated pulmonary IL-2 and IFN-gamma mRNAs, while an activated CD8(+) T cell peak was detect ed in MLN and lungs. Cell infiltration also occurred in MLN of BBG2Na-immun ized mice. However, there was no evidence of T cell, B cell, or granulocyte infiltration or activation in lungs, while transient transcription of Th1- type cytokine genes was evident The absence of pulmonary infiltration is un likely due to insufficient viral antigen. Thus, this recombinant fusion RSV G fragment does not prime for adverse pulmonary immunopathologic responses . (C) 1999 Academic Press.