DOSE-DEPENDENT SYSTEMIC HUMAN-IMMUNODEFICIENCY-VIRUS INFECTION OF SCID-HU MICE AFTER INTRAPERITONEAL VIRUS INJECTION

SCID mice were engrafted with human foetal liver, thymus and lung. Hum an cells were subsequently detected among peripheral blood leukocytes for 81% of tested animals and in tissue implants for 100% of tested an imals. SCID-hu mice received intraperitoneal injections of human immun odeficiency virus type 1 (HIV1) at from 20 up to 20,000 median tissue culture infectious doses (TCID50). HIV1 infection was detected by mean s of cell culture and polymerase chain reaction both in blood and impl ants, up to 58 days after infection. The rate of infection was depende nt upon the inoculated dose: the frequency of thymus infection ranged from 14% with 20-500 TCID50 up to 100% with 20,000 TCID50. HIV1 infect ion was detected less frequently in blood leukocytes than in thymus. T hymus virus load ranged from 40 to 50,000 HIV1 provirus copies per mil lion cells and was not correlated with either infectious dose or virae mia. Thymus T-cell depletion was observed mainly in the CD1(+)4(+)8(+) immature thymocyte compartment. The same rate of SCID-hu mouse infect ion was obtained using three different primary HIV1 isolates, suggesti ng that infection was not restricted to a few particular virus strains . The systemic infection of SCID-hu mice following intraperitoneal vir us injection mimics some traits of human HIV infection and provides a promising, novel approach for future investigations in this field.