TABLE 3.

Physicochemical characteristics of PMN chemoattractants in mastitic and normal late-lactation-stage milk^a

Milk type	Estimated molecular mass (kDa)b	Heat stabilityc	pH stability
			pH 2	pH 11
Mastitic	≥3–<10	Stable	NDd	ND
Normal late stage	≥10–<30	Unstable	Stable	74% activity loss

^aResults are representative of two separate experiments. 

^bMolecular mass estimations were made with centrifugal concentrators with cutoff filters of 3, 10, and 30 kDa. 

^cAt 60°C for 30 min. Stable, full chemotactic activity remained; unstable, complete absence of chemotactic activity. 

^dND, not determined.