Abstract: The glycosylphospholipid nucleoside derivatives of the invention are based on the formula: ##STR1## wherein: R.sub.1 is a nucleoside derivative selected from the group consisting of 3'-azidothymidine (AZT); 2', 3'-dideoxythymidine (ddT); and 2'-deoxy-5-fluorouridine (dFU);R.sub.2 is a hexose or pentose sugar, with the exception of glucose when x is 1;A is a hydrogen atom or an alkyl or alkoxy chain containing from 5 to 20 carbon atoms, said alkyl or alkoxy chain having at its extremity a group selected from the group consisting of a hydrogen atom and an NR'R" group, wherein R' and R" represent hydrogen or an alkyl group of 1 to 4 carbon atoms;x is a number from 1 to 12;y is a number from 1 to 4; andz is 0 or 1; and further wherein:attachment of said hexose sugar is at position 1 or position 6 of said hexose sugar, and attachment of said pentose sugar is at position 1 or position 5 of said pentose sugar.

Abstract: An immunostimulant from bacterial cells of Salmonella typhimurium or Listeria monocytogenes; it promotes non-specific resistance to pathogens which has no antigenic relationship to the immunostimulant.

Abstract: The immunostimulant agent is extracted from splenic cells of animal origin from Ehrlich ascites cells or from bacteria, such as Bacillus subtilis or Saccharomyces cerevisiae. A suspension of these cells or of these bacteria is formed with a mixture of solvents containing a halogenated hydrocarbon and an alcohol. The insoluble fractions are separated, the liquid fraction evaporated under reduced pressure and at reduced temperature, and the solid residue taken up again in chloroform. The chloroform solution containing the abovementioned immunostimulant agent is recovered by filtration. A suspension in an injectable liquid vehicle of the immunostimulant agent is in the form of particles or micelles whose dimensions are sufficiently small for said suspension to be injectable in man or animal.