The complement cascade
Produced in collaboration with Claudie Hooper.
Antibody-mediatedpathway activation

C1complex

C1s

C1s

C1q

C1r

Membrane attack complex

C4C3aPathogen

C4aC1 inhibitor
Pathway activation(through carbohydratebinding)
MAp19

C3 convertase
C2aC2

MBL/Ficolins
MASP1/2

Hydrolyzed

C3i’Tickover’

C2b+ Factor B

C4bp, Factor I
MCP, DAF and CR1

Pathway cross-talk

C3i

Stabilizes

Bb

Ampliﬁcation

Properdin
or factor P

BFactor DBaFactor H CD55
and CD35

DEF

K+ andCI- eﬄux

Formation of MAC andbacterial lysis

Stabilized
by invading
micro-organisms

Na+ andH2O inﬂux

GC5aC3 Convertase

C3C3bC3i

Bb3bC5 Convertase
C3aPW0238 2024/01 A

abcam.com

C5bC5C

Vitronectin, clusterin(plasma proteins) andCD59 on host cells.

C4b C2aFactor I, MCP
C3i

C4b C2b C3bChemotaxis andactivation ofinﬂammatory cells,
inducing cytokine
production and mastcell degranulation,
which results inenhanced vascularpermeability and local
blood ﬂow.

Inhibition of MAC
formation

MAp44

C3C5 convertase

C4bC3bB

Carboxypeptidase

C3C1rA

Copyright © 2024 abcam. All rights reserved.

Factor IKeyAbbreviations

Classical complement pathway

CR1

Complement receptors

Alternate pathway

MAC

Membrane attack complex

Lectin pathway

Complement pathway inhibitors

DAF

MBL

MCP

Decay-accelerating factor
Membrane-binding lectin

Membrane cofactor protein

KeyC5bC6C7C8C9

Related antibodies
Antibodies
C1q [JL-1]
C1r
C1s
C1s [EPR9066(E)]C2C2bC3a / C3a des Arg [4H3] - Azide free
C4C4aC4bC5 / C5a [2942]
C5b-9
C5b-9 [2A1]
C6C7 [EPR703]
C9
CD35 [E11] (FITC)
CD35 [EPR660
CD55 [143-30] (FITC)
CD55 [EPR668]
Factor B [KT21]
Factor D
Factor H
Factor H [EPR622]
Factor H [OX-24] (FITC)
Factor I [OX-21]
Ficolin 2
MASP1
MBL [3B6]
Properdin

Clonality
monoclonal
polyclonal
polyclonalmonoclonal
polyclonal
polyclonalmonoclonalmonoclonal
polyclonal
polyclonalmonoclonal
polyclonalmonoclonal
polyclonalmonoclonal
polyclonalmonoclonalmonoclonalmonoclonalmonoclonalmonoclonal
polyclonal
polyclonalmonoclonalmonoclonalmonoclonal
polyclonal
polyclonalmonoclonal
polyclonal

Applications
ELISA, Flow Cyt, FuncS, IHC-Fr, WB
WB
ICC/IF, WB
Flow Cyt, IHC-P, WB
ICC/IF, IHC-P, WB
WB
ELISA, IHC-P, WB
WB
WB
ICC/IF, IHC-P, WB
FuncS, IHC-Fr, IHC-P, WB
ICC/IF, IHC-FoFr, IHC-Fr, IHC-P, RID
ICC/IF, WB
ICC/IF, WB
Flow Cyt, ICC/IF, IHC-P, WB
IHC-P, WB
Flow Cyt, IHC-Fr, IHC-P, IP, WB
ICC, IHC-P, WB
Flow Cyt, IHC-Fr
IHC-P, WB
sELISA, WB
WB
IHC-P, WB
ICC, WB
Flow Cyt
ELISA, Flow Cyt, IHC-P, IP, WB
IP, WB
ICC/IF, WB
IHC-Fr, IHC-P, sELISA, WB
WB

Host
Ms
Rb
Rb
Rb
Rb
Rb
Ms
Ms
Rb
Rb
Ms
Rb
Ms
Rb
Rb
Rb
Ms
Rb
Ms
Rb
Ms
Rb
Rb
Rb
Ms
Ms
Rb
Rb
Ms
Rb

Species reactivity
Hu, Ms, Rat
Hu
Hu
Hu
Hu
Ms
Hu
RecFrag
Hu
Hu
Hu
Hu, MsRat
Hu
Hu, Ms, Rat
Hu
Hu
Hu
Hu, Pig
Hu
Hu
Hu
Hu
Hu
Hu
Hu
Hu
Hu
Hu
Hu

Product code
ab71940ab71652
ab66762
ab134943
ab77498
ab66999ab37230
ab54902ab87429
ab66791
ab11877
ab55811ab83076ab74638
ab126786
ab71330
ab82441
ab126737
ab25634
ab133684
ab110651
ab111204
ab112060
ab133536
ab112205
ab115312
ab118374
ab65891
ab121075
ab94597

Proteins/peptides
ab96363
ab116915
ab116902
ab116902
ab94384ab95402ab86260
ab114287
ab61918
ab51973ab90892
ab131766
ab95412ab114199
ab80038ab80038
ab73657
ab139231
ab131757
ab131757
ab131757
ab114924

Product highlights

C1q antibody [JL-1] (ab71940)
Immunohistochemical staining of C1q using
ab71940, in paraformaldehyde fixed, frozen rat
spleen tissue sections.
Clonality
Monoclonal
Applications
ELISA, Flow Cyt, FuncS, IHC-Fr, WB
HostMsSpecies cross reactivity
Hu, Ms, Rat

Related ELISA kits
Targets
Complement C3
Complement C3
Complement C3ades Arg
Complement C4Complement C4Complement C5Complement C6

Reacts with Assay type
Hu
Sandwich
Hu
Sandwich
Hu
Competitive

Sample type
Serum, Plasma
Cell culture supernatant, Saliva, Milk, Urine
PlasmaSensitivity
0.5 μg/ml
0.6 ng/ml
0.12 ng/ml

General range
30 - 0.47 μg/ml
40 - 0.625 ng/ml
20 - 0.313 ng/ml

Product codeab108822
ab108823
ab133037

EasyLink antibody conjugation kits

Hu
Hu
Hu
Hu

Sandwich
Sandwich
Competitive
Competitive

5 - 0.313 μg/ml
20 - 0.078 ng/ml
6 - 0.6 ng/ml
25 - 2.5 ng/ml

ab108824
ab108825
ab125963
ab125965

Complement C7

Hu

Competitive

Serum, Plasma
0.3 μg/ml
Cell culture supernatant, Saliva, Urine
0.08 ng/ml
Cell culture supernatant, Saliva, Milk, Serum, Plasma 0.3 ng/ml
Saliva, Milk, Urine, Serum, Plasma, Cell culture
0.7 ng/ml
extracts
Cell culture supernatant, Saliva, Milk, Urine, Serum, 0.6 ng/ml
Plasma10 - 1 ng/ml

ab125964

Histogram shows integrin beta-3 positive populationof platelets from WT and KO mice. The integrin
beta-3 antibody was conjugated using EasyLink R-PE
conjugation kit (ab102919). Mice expressing beta-3(red) had a clear shift in FL-2 fluorescence overbeta-3 KO mice (black).
Visit www.abcam.com/EasyLink for more details.

Discover more at abcam.com/complement

abcam.com

Copyright © 2024 abcam. All rights reserved.

EasyLink kits allow rapid conjugation of yourantibody to a wide choice of fluorescent labels
including tandem dyes.