title: Recirculating CD4 memory T cells mount rapid secondary responses without major contributions from follicular CD4 effectors and B cells.
abstract: For weeks after primary immunization with thymus-dependent antigens the responding lymph nodes contain effector CD4 T cells in T zones and germinal centers as well as recirculating memory T cells. Conversely, remote nodes, not exposed to antigen, only receive recirculating memory cells. We assessed whether lymph nodes with follicular effector CD4 T cells in addition to recirculating memory CD4 T cells mount a more rapid secondary response than nodes that only contain recirculating memory cells. Also, the extent to which T cell frequency governs accelerated CD4 T cell recall responses was tested. For this, secondary antibody responses to a superantigen, where the frequency of responding T cells is not increased at the time of challenge, were compared with those to conventional protein antigens. With both types of antigens similar accelerated responses were elicited in the node draining the site of primary immunization and in the contralateral node, not previously exposed to antigen. Thus recirculating memory cells are fully capable of mounting accelerated secondary responses, without the assistance of CD4 effector T cells, and accelerated memory responses are not solely dependent on higher T cell frequencies. Accelerated memory CD4 T cell responses were also seen in B cell-deficient mice.
authors.affiliation: Department of Biochemistry, University of Lausanne, Epalinges, Switzerland.
authors.forename: Sanjiv A
authors.initials: SA
authors.lastname: Luther
authors.forename: Karine
authors.initials: K
authors.lastname: Serre
authors.forename: Adam F
authors.initials: AF
authors.lastname: Cunningham
authors.forename: Mahmood
authors.initials: M
authors.lastname: Khan
authors.forename: Hans
authors.initials: H
authors.lastname: Acha-Orbea
authors.forename: Ian C M
authors.initials: IC
authors.lastname: MacLennan
authors.forename: Kai-Michael
authors.initials: KM
authors.lastname: Toellner
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D002452:Cell Count; D045304:Cytochromes c / Q000378:metabolism; D015870:Gene Expression; D007117:Immunization, Secondary; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007156:Immunologic Memory / Q000276:immunology*; D015847:Interleukin-4 / Q000235:genetics; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D008324:Mammary Tumor Virus, Mouse / Q000276:immunology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D009596:Nitrophenols / Q000276:immunology; D010648:Phenylacetates; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis / Q000276:immunology; D054400:Receptors, CCR7; D019707:Receptors, Chemokine / Q000378:metabolism; D014611:Vaccination
chemical_list: D015703:Antigens, CD; D000956:Antigens, Viral; C515371:Ccr7 protein, mouse; D007143:Immunoglobulin Heavy Chains; D008562:Membrane Glycoproteins; C095378:Mtv-7 superantigen, Mouse mammary tumor virus; D009596:Nitrophenols; D010648:Phenylacetates; D016693:Receptors, Antigen, T-Cell, alpha-beta; D054400:Receptors, CCR7; D019707:Receptors, Chemokine; C026242:4-hydroxy-5-nitrophenyl acetic acid; D015847:Interleukin-4; D045304:Cytochromes c