The effects of free and encapsulated allergens of Artemisia scoparia p
ollen on lymphocyte proliferation and immunoglobulin production in BAL
B/c mice were investigated. Splenic lymphocytes from mice immunized wi
th liposome entrapped allergen (LEA) elicited a marked proliferative r
esponse upon in vitro stimulation with both free and encapsulated alle
rgen in comparison to mice immunized with free allergen (FA). The seru
m immunoglobulin profile of mice administered LEA revealed a predomina
nce of IgG1 antibodies concomitant with an enhancement of IgG2a, IgG2b
, IgG3 and IgM responses and suppression of IgE responses. However imm
unization with FA resulted in significant production of IgE responses
and low levels of IgG antibodies. The differential ability of free and
encapsulated allergens to selectively induce immunoglobulin isotypes
suggests that different presentation and T cell differentiation pathwa
ys may be followed by FA and LEA in the immune system. Proliferation s
tudies involving macrophage depletion demonstrated that macrophages pl
ay an obligatory role in the processing of LEA. Analysis of cytokine p
roduction in sera of immunized mice (FA/LEA) revealed that LEA induced
significant IFN-gamma responses and lower IL-4 responses than mice im
munized with FA. The results of the present study indicate that liposo
mes synergise the proliferation by the antigen incorporated in it and
polarizes the response towards Thl type of cytokine production. The im
munoadjuvant and immunomodulation property of liposomes make it an eff
icient vehicle for effective immunotherapy.