Local passive immunoprophylaxy has been used in pulmonary
infectious diseases successfully. However, the short
immunoglobulins half-life in the lungs limits the duration of their action. The aim of the present study was to evaluate the efficiency of human polyvalent
intravenous immunoglobulins (
IVIG) when protected after encapsulation within
EPC:
DPPG liposomes by
dehydration/
rehydration. Two
IVIG concentrations were chosen: 10 and 1 mg/ml for further studies in mice infected by
influenza A. For the highest concentration (10 mg/ml),
IVIG loaded
liposomes did not significantly differ from
IVIG/unloaded
liposomes mixture with around 45% association yield. For the lowest concentration (1 mg/ml), two thirds of the
IVIG associated were found inside the vesicles. In vivo,
IVIG administered intranasally
at 10 mg/ml (500 microg per mouse) 4 days before the
infection led to 100% survival whatever the formulation. When administered at a lower dose (1 mg/ml-50 microg per mouse) 2 days before the challenge, loaded
liposomes were found less efficient than free
IVIG while unloaded
liposomes showed a slight aspecific immunoprotection. Gastrointestinal clearance must be responsible for a major loss of
liposomes compared to
IVIG solution because of a higher viscosity of the formulation. Discrepancies with the literature are discussed.