Effects of sleep on the splenic milieu in mice and the T cell receptor repertoire recruited into a T cell dependent B cell response

Abstract

Sleep is known to improve immune function ranging from cell distribution in the naïve state to elevated antibody titers after an immune challenge. The underlying mechanisms still remain unclear, partially because most studies have focused on the analysis of blood only. Hence, we investigated the effects of sleep within the spleen in female C57BL/6J mice with normal sleep compared to short-term sleep-deprived animals both in the naïve state and after an antigen challenge. Lack of sleep decreased the expression of genes associated with immune cell recruitment into and antigen presentation within the spleen both in the naïve state and during a T cell dependent B cell response directed against sheep red blood cells (SRBC). However, neither T cell proliferation nor formation of SRBC-specific antibodies was affected. In addition, the T cell receptor repertoire recruited into the immune response within seven days was not influenced by sleep deprivation. Thus, sleep modulated the molecular milieu within the spleen whereas we could not detect corresponding changes in the primary immune response against SRBC. Further studies will show whether sleep influences the secondary immune response against SRBC or the development of the B cell receptor repertoire, and how this can be compared to other antigens.

Sleep restriction prior to antigen exposure does not alter the T cell receptor repertoire but impairs germinal center formation during a T cell-dependent B cell response in murine spleen

“…Half of the mice (‘awake’ group) were kept awake for 6 ​h by gentle handling as described previously ( Hahn et al., 2020 ; Husse et al., 2012 ; Tune et al., 2020 ), while the other half was left completely undisturbed during this time period (‘sleep’ group). Immediately after this sleep (restriction) phase, both mouse groups were immunized by injection of 10 9 SRBC (Labor Dr. Merk, Ochsenhausen, Germany) in 200 ​μl PBS as described previously ( Stamm et al., 2013 ).…”

“…Digital images were taken using Axiophot Microscope and AxioCam (Carl Zeiss). Cell counts and GC area determination were performed with ImageJ (National Institutes of Health) as described previously ( Tune et al., 2020 ).…”

“…pneumonia incidence ( Patel et al., 2012 ), and sepsis outcome ( Friese et al., 2009 ) as well as a sleep-induced improvement of vaccination efficiency ( Benedict et al., 2012 ; Lange et al, 2003 , 2011 ; Spiegel et al., 2002 ). While the majority of these studies determined quantitative blood parameters like lymphocyte numbers, cytokine levels and antibody titers in humans, we used mice to investigate sleep effects on the milieu of secondary lymphoid organs (SLO) and found its impact to be more pronounced in spleen than in lymph nodes ( Tune et al., 2020 ). Accordingly, we determined the effects of sleep on the response to sheep red blood cells (SRBC), a blood born antigen processed in spleen.…”

“…Accordingly, we determined the effects of sleep on the response to sheep red blood cells (SRBC), a blood born antigen processed in spleen. When 6 ​h of sleep restriction followed the antigen challenge we found synchronized reductions in the expression of genes reflecting antigen presentation ( Tune et al., 2020 ). However, this did not have any significant long-term effects on the subsequent T cell-dependent B cell response, which prompted us to ask if the sleep induced changes in SLO milieu rather influence an upcoming immune response than an ongoing one.…”

“…However, none of these studies investigated the adaptive component of the immune system that is induced by antigen presentation and likely contributed to the observed differences in pathogen clearance and survival. To explore whether sleep restriction prior to an antigen exposure also affects the adaptive immune response we here repeated our previous study ( Tune et al., 2020 ) that combined 6 ​h of stress-free sleep restriction ( Hahn et al., 2020 ; Husse et al., 2012 ) with SRBC injection which evokes a well described T cell-dependent B cell response ( Stamm et al., 2013 ; Textor et al., 2018 ; Tune et al., 2020 ), but reversed the order of manipulations in such that sleep restriction preceded the antigen challenge. We searched for differences between sleep restricted mice and animals with undisturbed sleep in T cell proliferation and germinal center (GC) development, gene expression and the T cell receptor repertoire (TCR-R) as well as SRBC-specific antibody serum levels at the two most relevant time points, i.e.…”