Figure 2. α-lactalbumin vaccination delays and treats breast tumor growth.

(a) Growth of autochthonous breast tumors was significantly inhibited (P = 0.0004) in ten month old MMTV-neu mice immunized with α-lactalbumin at eight weeks of age. (b) Growth of transplanted 4T1 tumors was significantly inhibited (P = 0.0006) following prophylactic immunization with α-lactalbumin 13 days prior to tumor inoculation. (c) H&E staining of tissue extracted from the flank of a representative mouse 5 days after s.c. inoculation of 2×10⁴ 4T1 tumor cells confirms the presence of an established growing tumor (arrows) infiltrating the underlying connective tissue. Size bar = 100 μm. Significant inhibition of 4T1 tumor growth occurred when α-lactalbumin immunization occurred (d) 5 days after tumor inoculation (P < 0.01) and (e) 13 days after tumor inoculation (P < 0.01), (f) but not 21 days after tumor inoculation (P > 0.10). (g) Significant inhibition (P < 0.0006) in the growth of very aggressive autochthonous tumors occurred following α-lactalbumin immunization of MMTV-PyVT transgenic mice at 6 weeks of age. Tumors in MMTV-PyVT mice were amenable to measurement in only one direction. All error bars show ±SE. Each * indicates significance.