Copper deficiency during perinatal development: effects on the immune response of mice

Dietary copper (Cu) was restricted in Swiss albino mice during five discrete intervals over a 9-wk period of perinatal development: gestation only (G), lactation only (L), 3 wk postlactation (PL), 1 wk after birth through postlactation (2/3L + PL), and lactation plus postlactation (L + PL). Biochemical and immunological status of mice in copper-deficient (-Cu) treatment groups in models G and L did not differ from that of copper-adequate (+Cu) controls. Signs of severe copper deficiency, such as low liver copper levels, and significant reductions in activity of plasma ceruloplasmin and splenocyte Cu-Zn superoxide dismutase were most evident in 6-wk-old mice from two groups, -Cu 2/3L + PL and -Cu L + PL. Mice in these groups were anemic and had small thymuses and enlarged spleens compared to controls receiving +Cu treatment. The -Cu mice demonstrated impaired antibody (plaque-forming cells, PFC) response to sheep erythrocytes, and the attenuation was proportional to copper deficiency, as judged by liver copper levels. Total plasma IgM levels were not greatly altered by -Cu treatment except in model L + PL. Total IgG levels were markedly reduced in this group and in the -Cu 2/3L + PL group. The PFC response of mice in the -Cu PL group was normal even though signs of copper deficiency were evident; however, the PFC response was reduced when -Cu treatment was extended to 5 wk and was reversible by switching to +Cu treatment. Splenocyte reactivity to B- and T-cell mitogens was not greatly different between groups. Incorporation of thymidine into DNA in the absence of mitogen was higher in -Cu mice. It is evident that severity of copper deficiency is related to degree of impaired immunity. Furthermore, severity of copper deficiency is dependent on duration and time of initiation of dietary copper restriction.