Who coined the term "immune system"?

Question

Who coined the term "immune system"?

The OED lists the following as its earliest example of the term "immune system":

1943 Science 30 Apr. 406/1
Complement..is removed by the addition of an antigen and the corresponding rabbit antibody unrelated to the immune system to be analysed.

Answer 1

Translated from G. Toepfer, Historisches Wörterbuch der Biologie (2016), vol. 3, pp. 226–227:

Immune system

(...) The discovery of a specific immune system in vertebrates took place in the 20th century.⁸⁹ The immune system concept was already used sporadically in the first decades of the 20th century. Thus in 1909 E. Meyer and E. Emmerich reported their investigation of a “bacteriolytic immune system”⁹⁰ and in 1920 H. Schade spoke of the “hemolytic immune system, consisting of blood cells and associated hemolysin-amboceptor”.⁹¹ But until the 1950s, the expression covered primarily laboratory investigated defense reactions, viz. the reaction system of antigens and antibodies⁹² — the expression only solidified into the concept of a body’s defense system in the mid-60s, first under the name lymphoid system,⁹³ but soon thereafter as “immune system”.⁹⁴

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^{89 Cf. Moulin, A. M. (1989). The immune system: a key concept for the history of immunology. Hist. Philos. Life Sci. 11, 221–236.
90 Meyer, E. & Emmerich, E. (1909). Über paroxysmale Hämoglobinurie. Deutsches Archiv für klinische Medizin 96, 287–327: 305.
91 Schade, H. (1920). Die physikalische Chemie in der inneren Medizin: 135; cf. 2nd ed. (1923): 142.
92 Bier, O. G., Siqueira, M. & Osler, A. G. (1955). Studies on the mechanism of hypersensitivity phenomena 1. Internat. Arch. Allergy Appl. Immunol. 7, 1–9: 5.
93 Cooper, M. D., Peterson, R. D. & Good, R. A. (1965). Delineation of the thymic and lymphoid system in the chicken. Nature 205, 143; (...)
94 New York Times, 24 Oct. 1965: IV. 8/3 (after OED).}