Antibodies for granddaughters

Scientists from the Sorbonne University have demonstrated that the effect of an alien agent on female urban pigeon Columba livia in the first generation forms an immune profile in their descendants after two generations. The results of their study are published in the November issue of the journal Biology Letters (Ismail et al., Transfer of human immunity over two generations in urban pigeons – VM).

The mechanism of passive protection of the developing immune system of the fetus is known: in all vertebrates, mothers transmit specific antibodies (MatAb) to their offspring, "teaching" their immunity to defend against pathogenic parasites. However, there is evidence to suggest that MatAb has an effect for longer, over two generations.

For two years, a group led by Julier Gasparini investigated the formation of antibodies to a foreign protein (antigen) in three generations of pigeons. As an antigen, the researchers used the protein KLH (keyhole limpet haemocyanin), which carries oxygen in the hemolymph of some invertebrates, including the marine mollusk Megathura crenulata. KLH is a completely new antigen for pigeons, so the possibility of developing specific antibodies to it before the start of the study was practically excluded. 

During this experiment, 60 females of the first generation (F0) were injected with KLH. Two weeks later, the antigen was re-injected to verify the difference in the level of antibodies to KLH compared to the control group of 60 females who were injected with a phosphate-salt solution. The next generation, F1 (the offspring of the first generation F0), received antigen injections at the age of 21 and 35 days. The reproduction of the second generation of pigeons was observed for a year, then their descendants (F2) were injected with a solution of KLH on the 21st and 35th days of life. The dynamics of the development of immunity was tracked by taking blood samples of pigeons at different ages.

As a result of this study, scientists found that immunization of "grandmothers" from generation F0 did not affect the concentration of antibodies against KLH in the egg yolks of their daughters in the next generation. However, already in F2, the concentration of antibodies increased with age only in those females whose grandmothers were also immunized.

The level of antibodies against the KHL antigen in the blood of pigeons-"granddaughters", 

whose "grandmothers" were (black) or were not (white) immunized.

Image: A. Ismail et al., Biology Letters, 2015

The exact mechanism of this phenomenon has not yet been studied, but the discovered new property of the immune system seems intriguing and definitely worth further research. The question of whether human immunity has a similar ability is also relevant.