Saif L J, Bohl E H
Ann N Y Acad Sci. 1983 Jun 30;409:708-23. doi: 10.1111/j.1749-6632.1983.tb26910.x.
Sows were injected intramammarily with live-attenuated TGE virus, an enteric coronavirus--one sow during pregnancy and three sows during lactation. All sows were TGE antibody seronegative prior to inoculation except for one naturally infected sow inoculated during lactation. The animal injected during pregnancy had primarily IgG TGE antibodies in milk from all glands. By contrast, sows injected during lactation had IgA and IgM initially, and later IgA and IgG TGE antibodies in milk from injected and noninjected glands. The seropositive sow had elevated IgA TGE antibody titers in milk after IMm injection. Both seronegative sows inoculated intramammarily during lactation shed TGE virus in milk from injected glands, and their nursing piglets developed mild diarrhea and shed virus in their feces at three to nine DPE of the sows. Milk from IMm injected glands generally had higher TGE antibody titers than milk from noninjected glands. These results suggest that TGE virus replicates in lactating mammary gland tissue, thereby stimulating IgA immunocytes, leading to secretion of IgA antibodies in milk. Whether the intramammary route presents a natural route of enteric virus exposure in lactating animals (by way of infected nursing piglets), leading to IgA-antibody secretion in milk, requires further investigation.
母猪经乳腺内注射了减毒活的猪传染性胃肠炎（TGE）病毒，这是一种肠道冠状病毒——一头母猪在妊娠期注射，三头母猪在哺乳期注射。除了一头在哺乳期自然感染的母猪外，所有母猪在接种前TGE抗体血清学检测均为阴性。妊娠期注射的母猪所有乳腺分泌的乳汁中主要是IgG TGE抗体。相比之下，哺乳期注射的母猪乳汁中最初是IgA和IgM，后来在注射和未注射乳腺分泌的乳汁中出现了IgA和IgG TGE抗体。血清阳性的母猪在乳腺内注射后乳汁中IgA TGE抗体滴度升高。哺乳期经乳腺内注射的血清阴性母猪，其注射乳腺分泌的乳汁中排出TGE病毒，其哺乳仔猪在母猪接种后3至9天出现轻度腹泻，粪便中排出病毒。经乳腺内注射的乳腺分泌的乳汁中TGE抗体滴度通常高于未注射乳腺分泌的乳汁。这些结果表明，TGE病毒在泌乳乳腺组织中复制，从而刺激IgA免疫细胞，导致乳汁中分泌IgA抗体。乳腺内途径是否是泌乳动物肠道病毒暴露（通过感染哺乳仔猪）的自然途径，从而导致乳汁中分泌IgA抗体，需要进一步研究。
