Glucan preparations

A method of stimulating the immune system of a patient comprising:

• administering to the patient a composition comprising underivatized, soluble β-glucan derived from Saccharomyces cerevisiae and having immunostimulatory properties and an average molecular weight between about 120,000 Da and about 205,000 Da;
• soluble β-glucan having a molecular weight over 380,000 Da in an amount less than or equal to 10%;
• and β-glucan having a molecular weight under 25,000 Da in an amount less than or equal to 17%,
• wherein the underivatized, soluble β-glucan is prepared by applying pressure to a suspension comprising particulate β-glucan and acetic acid, and heating the suspension for a time sufficient to form the soluble β-glucan, wherein the suspension is buffered to a pH of about 3.6, and where the underivatized, soluble β-glucan is not treated with caustic solution during preparation.

A method of mobilizing stem cells of a patient comprising:

• administering to the patient a composition comprising underivatized, soluble β-glucan derived from Saccharomyces cerevisiae and having immunostimulatory properties and an average molecular weight between about 120,000 Da and about 205,000 Da;
• soluble β-glucan having a molecular weight over 380,000 Da in an amount less than or equal to 10%;
• and β-glucan having a molecular weight under 25,000 Da in an amount less than or equal to 17%,
• wherein the underivatized, soluble β-glucan is prepared by applying pressure to a suspension comprising particulate β-glucan and acetic acid, and heating the suspension for a time sufficient to form the soluble β-glucan, wherein the suspension is buffered to a pH of about 3.6, and where the underivatized, soluble β-glucan is not treated with caustic solution during preparation.

A method treating cancer in a patient comprising:

• administering a cytoreductive therapy to the patient;
• and
• administering a composition comprising soluble β-glucan having a molecular weight over 380,000 Da in an amount less than or equal to 10%;
• and β-glucan having a molecular weight under 25,000 Da in an amount less than or equal to 17%,
• wherein the underivatized, soluble β-glucan is prepared by applying pressure to a suspension comprising particulate β-glucan and acetic acid, and heating the suspension for a time sufficient to form the soluble β-glucan, wherein the soluble β-glucan is purified by hydrophobic interaction chromatography.