Method for the production of protein complexes and vaccine compositions comprising the same

A method for production of a composition comprising stress protein complexes formed between a stress protein and a peptide, the method comprising:

• (a) culturing cells;
• (b) exposing said cells to at least two stress inducing stimuli of different types wherein a first stress inducing stimulus is heat and a second stress inducing stimulus is respiratory stress or acid based stress,
• wherein the respiratory stress comprises decreasing or increasing the amount of oxygen to which the cells are exposed, and
• wherein the acid based stress comprises reducing the pH of the cells below the pH that causes normal physiological growth or homeostasis of the cells;
• (c) producing stress protein complexes having increased yield and immunogenicity when compared to stress protein complexes produced with exposure to only the first or second stress inducing stimulus;
• (d) lysing the cells to produce a cell lysate;
• (e) clarifying the cell lysate to produce a clarified cell lysate;
• (f) purifying the stress protein complexes from the clarified cell lysate;
• (g) subjecting the clarified cell lysate to purification using ion exchange, wherein the clarified cell lysate is buffered to a pH within 2 units of the pI of the stress protein complexes;
• (h) eluting the stress protein complexes with a salt gradient;
• and
• (i) obtaining an enriched preparation comprising the stress protein complexes.