Major differences between the two vaccine antigens of C. albicans under clinical trial

Als 3	Sap 2
A cell surface, GPI protein member of Als adhesin family without known enzymatic activity: Interacts with various members of host integrin family	A major member of secreted aspartic proteinase family of C. albicans with direct or indirect adhesin activity. May interact and hydrolyze various host immunologically relevant proteins such as complement antibodies and epithelial structural proteins such as E-cadherin
Involved in biofilm formation	No apparent role in biofilm (other members of Sap family may be involved)
Modulates iron acquisition by hyphae	A classical metabolic role as proteinase of C. albicans, both in yeast and hyphae
Candida-colonized subjects have both CMI and Ab responses against Als 3	Low or no levels of antibodies and CMI responses in Candida- colonized subjects, likely because of Sap2 low immunogenicity in its natural form
Vaccine induces protection through elicitation of Th1 and Th17 cells, then the cohort of antifungal humoral and cellular factors acting locally and promoting inflammation	Vaccine induces protection through elicitation of neutralizing antibody at vaginal level.
Vaccine target: candidiasis systemic and mucosal	Vaccine target: recurrent vulvovaginal candidiasis